Fluid Mechanics Flashcards by Kris Daclan

The fluid property, due to which, mercury does not wet the glass is
surface tension
viscosity
cohesion
adhesion

surface tension

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Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds
4000
2100
1500
3000

2100

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When the momentum of one fluid is used for moving another fluid, such a device is called a/an ____.
jet pump
blower
acid egg
none of these

jet pump

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The normal stress is the same in all directions at a point in a fluid, when the fluid is
non-viscous.
incompressible.
both (a) and (b).
having no motion of one fluid layer relative to the other.

having no motion of one fluid layer relative to the other.

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Head developed by a centrifugal pump depends on its ____.
speed
impeller diameter
both (a) and (b)
neither (a) nor (b)

both (a) and (b)

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Hydraulic mean depth (Dm) for a circular pipe of diameter ‘D’ flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum ______.
flow rate
mean velocity
both ‘a’ & ‘b’
neither ‘a’ nor ‘b’

mean velocity

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The head loss in turbulent flow in a pipe varies
as velocity
as (velocity)^2
inversely as the square of diameter
inversely as the velocity

as (velocity)^2

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Most commonly used joint in the underground pipe lines is the
sleevejoint
coupling
flange
expansion joint

sleevejoint

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Schedule number of a pipe, which is a measure of its wall thickness, is given by
1000 P’/S
100 P’/S
1000 S/P’
10000 P’/S

1000 P’/S

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The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the ______.
discharge.
suction.
suction minus vapor pressure of the liquid at suction temperature.
discharge minus vapor pressure of the liquid at the discharge temperature.

suction minus vapor pressure of the liquid at suction temperature.

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With increasing flow rate, the hydraulic efficiency of a centrifugal pump
monotonically decreases.
decreases and then increases.
remains constant.
increases and then decreases.

monotonically decreases.

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The velocity profile for turbulent flow through a closed conduit is
logarithmic
parabolic
hyperbolic
linear

logarithmic

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In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of
relative roughness.
absolute roughness.
friction co-efficient for flows at equal Reynold number.
all (a), (b) & (c).

friction co-efficient for flows at equal Reynold number.

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Water hammer in a pipeline results from the
bursting of pipelines due to closure by a valve.
rapid pressure change due to a rapid change in the rate of flow.
pressure increase due to closure of a valve resulting in decrease in rate of flow.
none of these.

rapid pressure change due to a rapid change in the rate of flow.

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Molten soap mass is transported by a __________ pump.
diaphragm
reciprocating
gear
centrifugal

centrifugal

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Which of the following denotes the effect of compressibility in fluid flow ?
Weber number
Mach number
Euler number
Reynolds number

Mach number

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Nominal size of the discharge pipe of a pump is usually __________ the nominal size of the inlet pipe.
smaller than
larger than
same as
twice

smaller than

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The terminal velocity of a small sphere settling in a viscous fluid varies as the
first power of its dimeter.
inverse of the fluid viscosity.
inverse square of the diameter.
square of the difference in specific weights of solid & fluid.

inverse of the fluid viscosity.

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If the discharge of a centrifugal pump is throttled, then its suction lift
increases
decreases
remains unchanged
data insufficient to predict

increases

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Foot valves provided in pumps are __________ valves.
relief
three/four way
pressure reducing
directional control

directional control

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At high Reynolds number
inertial forces control and viscous forces are unimportant.
viscous forces predominate.
inertial forces are unimportant and viscous forces control.
none of these.

inertial forces control and viscous forces are unimportant.

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Power loss in an orificemeter is __________ that in a venturimeter.
less than
same as
more than
data insufficient, cannot be predicted

more than

due to the sudden contraction and expansion of fluid stream in orificemeter

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The terminal velocity of a particle moving through a fluid varies as (dp)^n. What is the value of n for Newton’s law regime ?
0.5
1
1.5
3

0.5

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What is the normal range of exit cone angle of a venturimeter ?
2 to 5
7 to 15
15 to 25
>25

7 to 15

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The dimension of dynamic viscosity is ML^-1T^-1 L^2T^-1 LT^-2 ML^-1T^-2

ML^-1T^-1

A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke's law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity same as that of A. one fourth as that of A. twice as that of A. four times as that of A.

one fourth as that of A.

The pitot static tube does not measure the __________ pressure. static total difference in static & dynamic all (a), (b) and (c)

all (a), (b) and (c)

The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a __________ fluid. Bingham Newtonian perfect none of these

Newtonian

The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is 0.5 1 1.5 2

The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10-6m2/s). 24000 24 0.24 0.44

0.44

For Laminar flow through a packed bed, the pressure drop is proportional to (Vs is the superficial liquid velocity and Dp is the particle diameter) Vs/Dp^2 Vs^2/Dp^2 Vs^2/Dp^3 Vs/Dp^3

Vs/Dp^2

The maximum delivery pressure of compressors can be upto __________ atmospheres. 10 100 250 1000

1000

Dimension of surface tension is(where, F = force, L = length) F*L^-1 F^-1*L F*L^-2 F^-2*L

F*L^-1

Which of the following is not a dimension-less parameter ? Euler number Specific gravity Fanning friction factor None of these

None of these

Co-efficient of velocity is __________ the coefficient of discharge. less than more than equal to not related to

more than Due to energy loss from friction and turbulence

All pipes of a particular nominal size have the same inside diameter outside diameter thickness none of these

outside diameter

For the transfer of solution of thick slurry, the pump used is a __________ pump. reciprocating gear diaphragm centrifugal

diaphragm

Which of the following is not concerned with the fluid-particle interaction ? Drag co-efficient Froude number Galileo number Weber number

Weber number Only concerned with the interaction of the fluid with itself. Wb = kinetic energy/surface energy

Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be __________ ft. 40 34 8 37

Pressure drag does not depend upon the roughness of surface of the body. pressure of main flow only. length of the body in flow direction. all (a), (b) and (c)

all (a), (b) and (c)

Dimension of absolute viscosity is ML-1T-1 MLT-1 ML-1T MLT

ML-1T-1

__________ pumps are axial flow pumps. Turbine Propeller Diffuser none of these

Propeller

Brownian movement is prominent in the particle size range of __________ microns in case of settling of a particle in a fluid. 2 to 3 0.01 to 0.10 200 to 300 100 to 1000

2 to 3

For a particle settling in water at its terminal settling velocity, which of the following is true ? Buoyancy = weight + drag Weight = buoyancy + drag Drag = buoyancy + weight Drag = weight

Weight = buoyancy + drag

A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, τ0 = 10 KPa, is shared between flat parallel plates separated by a distance of 10-3 m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is 10 KPa 20 KPa 30 KPa 40 KPa

20 KPa

Pick out the correct statement. A forced vortex occurs when fluid rotates as a solid about an axis. In laminar flow, Newton's law of viscosity does not apply. A free vortex occurs, when fluidrotates as a solid. In turbulent flow, there are neither cross-currents nor eddies.

A forced vortex occurs when fluid rotates as a solid about an axis.

Shear stress in a fluid flowing in a round pipe varies parabolically across the cross-section. remains constant over the cross-section. is zero at the centre and varies linearly with the radius. is zero at the wall and increases linearly to the centre.

is zero at the centre and varies linearly with the radius.

The resistance wire used in a hot wire anemometer for conducting electrical current is made of copper tungsten chromium aluminium

tungsten due to its high melting point and electrical resistance

Two dimensional stream function relates velocity and pressure. is constant along a stream line. is constant along an equipotential surface. none of these.

is constant along a stream line.

What causes cavitation in centrifugal pump ? High suction pressure Low barometric pressure Low suction pressure High suction velocity

Low suction pressure Cavitation - when pressure of a liquid drops below its vapor pressure forming bubbles

Draining of shallow pits or sump is done by a sump pump, which is a __________ pump. single stage vertical centrifugal plunger diffuser

single stage vertical

A hydraulic ram acts as a/an __________ pump. centrifugal reciprocating impulse parallel cylinder

impulse

The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonion fluid in a circular pipe is _____. 0.5 1 2 0.66

0.5

Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively). FL-2T, ML-1T-1 FLT, ML-1T-1 ML-1T-3, F-1L2T F-1L2T-1, MLT-3

FL-2T, ML-1T-1

he line of action of the buoyant force passes through the centre of gravity of the submerged body. displaced volume of the fluid. volume of fluid vertically above the body. horizontal projection of the body.

displaced volume of the fluid.

Pick out the wrong statement. The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonion fluids is In the equation, the value of 'n' for pseudoplastic and dilatant fluids are < 1 and >1 respectively. Shear stress for Newtonion fluid is proportional to the rate of shear in the direction perpendicular to motion. With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids.

With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids.

The friction factor for turbulent flow in a hydraulically smooth pipe _____. depends only on Reynolds number. does not depend on Reynolds number. depends on the roughness. none of these.

depends only on Reynolds number.

The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and _____. moving static cold hot

moving

What causes convective acceleration in fluid flow ? Steep slope in flow Unsteady nature of flow Non-uniformity of flow Turbulence in flow

Non-uniformity of flow

The Stoke's stream function applies to the irrotational flow only. ideal/non-viscous fluids only. cases of axial symmetry. none of these.

cases of axial symmetry.

Slugging in a fluidised bed can be avoided by using _____. tall narrow vessel. deep bed of solids. shallow beds of solids and proper choice of particle size. very large particles.

shallow beds of solids and proper choice of particle size.

The ratio of width to depth for the most economical rectangular section in open channel flow is 0.5 1 1.5 2

The simple pitot tube measures the __________ pressure. static dynamic total none of these

total

Capacity of a hydraulic accumulator is defined in terms of maximum ______. amount of energy stored. flow rate through accumulator. rate of falling of ram. volume available in the cylinder.

amount of energy stored.

With diminishing cross-sectional area in case of subsonic flow in a converging nozzle, the velocity increases pressure decreases both (a) & (b) neither (a) nor (b)

both (a) & (b)

Boundary layer separation is characterised by one of the conditions given below, where 'Re' is the Reynolds number for the flow. Select the appropriate conditions. Re << 1, accelerating flow Re >> 1, accelerating flow Re << 1, decelerating flow Re >>1, decelerating flow

Re >>1, decelerating flow This condition is conducive to adverse pressure gradient which separate a fluid from the surface.

Manometers measure the __________ pressure. vacuum as well as the atmospheric difference in absolute gage

difference in

Which of the following fluid forces are not considered in the Navier-Stoke's equation? Gravity forces Viscous forces Pressure forces Turbulent forces

Turbulent forces

Which of the following may be termed as a variable orifice flowmeter ? Rotameter Pitot tube V-notch All (a), (b) and (c)

Rotameter

In turbulent flow, a rough pipe has the same friction factor as a smooth pipe ______. in the zone of complete turbulence. when the roughness projections are much smaller than the thickness of the laminar film. everywhere in the transition zone. when the friction factor is independent of the Reynold's number.

when the roughness projections are much smaller than the thickness of the laminar film.

Air vessel provided in a reciprocating pump _______. smoothens the flow by avoiding pulsations. increases the volumetric efficiency of the pump. saves the pump from the danger of cavitation. none of these.

none of these.

Bernoulli's equation is dependent on the first law of thermodynamics. third law of thermodynamics. law of conservation of momentum. none of these.

none of these.

The capacity of an accumulator is the maximum energy which it can store. discharge which it can deliver. liquid which it can store. none of these.

energy which it can store.

With increase in the temperature, viscosity of a liquid increases decreases remains constant may increase or decrease; depends on the liquid

decreases

Vena-contracta pressure tapping is at a distance __________ from the position of an orificemeter fitted in a pipe of internal diameter 'd' d 0.5 d 2d 4d

0.5 d

The pump impeller and the turbine runner in a hydraulic torque converter have the same diameter. have different diameters. are directly coupled. none of these.

have different diameters.

Reciprocating pumps compared to centrifugal pumps ______. deliver liquid at uniform pressure. can handle slurries more efficiently. are not subject to air binding. can be operated with delivery valve closed.

are not subject to air binding.

The fluid property which matters for fall-ing rain drops to acquire spherical shape is its _____. pressure height of descend viscosity surface tension

surface tension

The simple pitot tube does not measure the static pressure. dynamic pressure. velocity at the stagnation point. all (a), (b) and (c).

all (a), (b) and (c).

Boundary layer separation occurs when the _____. pressure reaches a minimum. cross-section of the channel is reduced. valve is closed in a pipeline. velocity of sound is reached.

cross-section of the channel is reduced.

The head loss in turbulent flow in a pipe varies _____. directly as the velocity. inversely as the square of the velocity. approximately as the square of the velocity. inversely as the square of the diameter.

approximately as the square of the velocity.

The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is 0.3 0.9 0.03 0.66

0.3

For the free settling of a spherical particle through a fluid, the slope of, CD-log NRe , plot is 1 -1 0.5 -0.5

-1

A centrifugal pump loses prime after starting. The reason of this trouble may be incomplete priming. too high a suction lift. low available NPSH and air leaks in the suction pipe. all (a), (b), and (c).

all (a), (b), and (c).

Venturimeter and orificemeter measures the __________ of the fluid. pressure maximum velocity average velocity point velocity

average velocity

Surge tanks are provided in high pressure water pipelines to ______. store a definite quantity of water all the time, reduce the water hammer. facilitate easy dismantling of pipeline for cleaning and maintenance. none of these.

reduce the water hammer.

Working principle of manometer comprises of balancing a coloumn of liquid against the pressure to be measured. Inclined tube manometer is especially used for the measurement of __________ pressure. small differential atmospheric absolute gage

small differential

Isotropic turbulence occurs where there is no velocity gradient. at higher temperatures. only in Newtonion fluids. none of these.

where there is no velocity gradient.

The co-efficient of drag and lift for an incompressible fluid depends on the _____. Reynolds number Froude number Mach number all (a), (b) and (c)

Reynolds number

Euler's equation of motion states, that at every point, the fluid momentum is constant. force per unit mass equals acceleration. rate of mass outflow is equal to the rate of mass inflow. none of these.

force per unit mass equals acceleration.

The Navier-Stokes equation deals with the law of conservation of mass energy both (a) & (b) momentum

momentum

Hydraulic intensifier is used for increasing the _____. rate of velocity of liquid supply. rate of flow through delivery pipeline of a pump. intensity of pressure of the liquid. momentum rate through delivery pipe.

intensity of pressure of the liquid.

Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of powder & grannular solids liquids low melting point semi-solids all 'a', 'b' & 'c'

all 'a', 'b' & 'c'

Euler's equation of motion is a statement expressing conservation of mass. conservation of energy. Newton's first law of motion. Newton's second law of motion.

conservation of mass.

Pick out the wrong statement. The form drag is dependent upon the occurrence of a wake. The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance. An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity. Existence of the boundary layer in fluid flow is because of viscosity of the fluid.

An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity.

Mass velocity is independent of temperature & pressure, when the flow is unsteady through unchanged cross-section. steady through changing cross-section. steady and the cross-section is unchanged. unsteady and the cross-section is changed.

steady and the cross-section is unchanged.

Very small pressure difference (< 5 mm water coloumn) can be most conveniently measured by a/an __________ manometer. U-tube water. U-tube mercury. inclined tube mercury. inclined tube water.

inclined tube water.

For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter). 1/D 1/D2 1/D5 D2

1/D5

For a given Reynold number as d/D for an orifice increases, Cd will (where, d & D are orifice & pipe diameters respectively). increase decrease remain constant either (a) or (b); depends on other factors

increase

The energy equation, E + P/ρ + v2/2g + gZ = constant (E = internal energy/mass), is applicable to: perfect gases only. isothermal flow of gases. adiabatic unsteady flow of gases. all compressible fluids.

all compressible fluids.

What is the ratio of fluid carrying capacity of two pipes having diameters d1 and d2 respectively? (d1/d2)^0.8 (d1/d2)^0.5 (d1/d2) (d1/d2)^2

(d1/d2)^0.5

A differential pressure cell is used for measuring small pressure difference in gases. measuring small pressure difference in liquids. remote recording of pressure difference. measuring the difference of the impact & the static pressure.

remote recording of pressure difference.

If more than two branches of pipes are to be connected at the same point, then use a/an elbow union tee none of these.

tee

In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. manometric mechanical volumetric overall

manometric

Acceleration head in a reciprocating pump increases the work done during delivery stroke. decreases the work done during suction stroke. does not change the work requirement of the pump. increases the work done during suction stroke.

does not change the work requirement of the pump.

The ratio of inertial forces to elastic forces is called the __________ number. Reynolds Mach Euler Weber

Mach

The equivalent diameter for flow through a rectangular duct of width B and height H is HB/2(H+B) HB/(H+B) 2HB/(H+B) 4HB/(H+B)

2HB/(H+B)

Fluid flow at increasing rate through a diverging pipe is an example of __________ flow. steady uniform non-steady uniform steady non-uniform non-steady non-uniform

non-steady non-uniform

The temperature in isentropic flow does not depend on Mach number. depends on Mach number only. cannot drop and then increase again downstream. none of these.

depends on Mach number only.

A fluid element has a velocity V = -y2 . xi + 2yx2 . j. The motion at (x, y) = (l/2, 1) is rotational and incompressible rotational and compressible irrotational and compressible irrotational and incompressible

rotational and compressible

Check in a centrifugal pump is provided in the discharge line. generally a globe valve. provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running. all (a), (b) and (c).

all (a), (b) and (c).

Drag force acting on a body does not depend upon the ____. density of the fluid. density of the body. velocity of the body. projected area of the body.

density of the body.

Centrifugal pump is normally classified on the basis of the _____. rpm. type of casing. impeller blade angle. number of blades in impeller.

type of casing.

Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter 'd'? At the centre At d/4 from the wall At the wall At d/8 from the wall

At the wall

In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where, T = absolute temperature ) 1/√T 1/T √T T

√T

Applying a pressure drop across a capillary results in a volumetric flow rate 'Q' under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is Q/2 Q/4 Q/8 Q/16

Q/16

Cd, Cc and Cv are related (for flow through an orifice) as (where, Cd = discharge co-efficient, Cc = co-efficient of contraction = [area of jet at vena-contracta/area of opening], Cv = co-efficient of velocity = [actual velocity at vena-contracta/theo velocity]) Cd = Cc/Cv Cd = Cc*Cv Cd = Cv/cc none of these

Cd = Cc*Cv

In an incompressible fluid, the density is greatly affected by moderate changes in pressure. greatly affected only by moderate changes in temperature. not affected with moderate change in temperature & pressure. sensible to changes in both temperature & pressure.

not affected with moderate change in temperature & pressure.

Check valves are used at high pressure. in bends. for controlling water flow. for unidirectional flow.

for unidirectional flow.

Velocity distribution for flow between two fixed parallel plates varies parabolically across the section. is constant over the entire cross-section. is zero at the plates and increases linearly to the midplane. none of these.

varies parabolically across the section.

Priming is needed in a __________ pump. reciprocating gear centrifugal diaphragm

centrifugal

An ideal nozzle design aims at minimising wall friction. suppressing boundary layer separation. both (a) & (b). neither (a) nor (b).

both (a) & (b).

Which of the fluid forces are not considered in the Reynold's equation of flow ? Viscous forces Turbulent forces Pressure forces Compressibility forces

Compressibility forces

For ideally incompressible fluid, the Mach number will be 1.5 1 0 5

A mono pump is a __________ pump. centrifugal piston positive acting rotary a group of vacuum

positive acting rotary

Higher specific speed (200-500) of a centrifugal pump indicates that the pump is of __________ flow type. axial radial mixed none of these

axial

The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost are P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet. P, Q and R P and R R and S P, Rand S

P, Q and R

Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller. radius of speed of fluid velocity leaving none of these

none of these

An ideal fluid is non-viscous incompressible both (a) & (b) neither (a) & (b)

both (a) & (b)

In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where M = molecular weight of the gas) 1/√M √M 1/M M

1/√M

Boundary layer separation is caused by the reduction of pressure to vapour pressure. boundary layer thickness reducing to zero. adverse pressure gradient. reduction of pressure gradient to zero.

adverse pressure gradient.

With increase in temperature, the vapor pressure of liquids increases increases linearly decreases remains constant

increases

A mercury (specific gravity = 13.6) manometer connected across an orificemeter fitted in a pipe shows a manometer reading of 2 cms. If the manometer liquid is changed to carbon tetrachloride (specific gravity = 1.6), then for the same flow rate of water the new manometer reading will be __________ cms. 17 42 84 1.8

The ratio of wall drag to total drag in the Stoke's law range is 0.5 1 1/3 2/3

2/3

Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg. 1 0.1 0.01 0.001

0.01

A pitched-blade turbine draws __________ a straight blade turbine. less power than more power than same power as data insufficient to predict

less power than

The most suitable flow measuring device for the fluid flow measurement in a very large diameter pipeline is a weir pitot tube Kennison nozzle V-notch

pitot tube

A centrifugal pump is called a turbine pump, if it is having a turbine type impeller. vaned diffusion casing. rotating vaned volute. none of these.

vaned diffusion casing.

Remote control valve is a __________ valve. gate butterfly needle globe

butterfly

Which of the following quantities are computed by using the hydraulic radius for non-circular ducts ? Velocity and relative roughness. Head loss and velocity. Reynold number, relative roughness and head loss. Reynolds number and friction factor.

Reynold number, relative roughness and head loss.

Centre of pressure in an immersed body is __________ the centre of gravity. above below at either above or below; depends on the liquid density

below

The centre of pressure is always below the centroid of the area. always above the centroid of the area. a point on the line of action of the resultant force. at the centroid of the submerged area.

a point on the line of action of the resultant force.

The uniformity of a gas fluidised bed depends upon the __________ of the solid particles. size surface properties both (a) and (b) neither (a) nor (b)

both (a) and (b)

Pascal law is not applicable for a/an __________ fluid. accelerating frictionless static uniformly moving none of these

none of these

In a fluidised bed reactor temperature gradients are very high. temperature is more or less uniform. hot spots are formed. segregation of the solids occurs.

temperature is more or less uniform.

The flow of a liquid through tapering pipe at a constant rate is an example of __________ flow. steady uniform steady non uniform unsteady uniform unsteady non uniform

steady non uniform

Pick out the correct statement pertaining to transition/ entrance length in fluid flow. The length of entrance region of pipe, in which full development of fluid flow takes place such that velocity profile does not change downstream, is called the transition length. Transition length for laminar flow of Newtonion fluids in a pipe of diameter 'd' is equal to 0.05. D.NRe. Transition length for turbulent flow of Newtonion fluids in a smooth pipe of diameter 'd' is equal to 50 D. all (a), (b) and (c).

all (a), (b) and (c).

A perfect gas ____. does not satisfy PV= nRT. is incompressible and has zero viscosity. has constant specific heat. can't develop shear stresses.

has constant specific heat.

In a/an __________ , the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure. rotameter pitot tube venturimeter flow nozzle

pitot tube

Speed of sound in an ideal gas depends on its ____. temperature pressure specific volume none of these

temperature

A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp). less head & capacity more head more capacity less head & more capacity

less head & capacity

If 'x' is the depth of flow in an open channel of large width, then the hydraulic radius is equal to x x/2 x/3 2x/3

In fluid flow, the boundary layer separation can not occur in case of boundaries experiencing form drag. at points of abrupt changes in the flow directions. in laminar flow. none of these.

none of these.

For a given fluid flow rate, which of the following incurs maximum head loss ? Orifice meter Venturimeter Flow nozzle All of them incur the same head loss

Orifice meter

Which of the following assumptions enables the Euler's equation of motion to be integrated ? The fluid is incompressible. The fluid is non-viscous. The continuity equation is satisfied. The flow is rotational and incompressible.

The fluid is incompressible.

In case of a pipe exit fitted with a nozzle, the conversion of kinetic head to pressure head is facilitated. conversion of pressure head to kinetic head is facilitated. power transmitted through the nozzle is maximum, when the head lost due to friction in the pipe is equal to one third of the total supply head. both (b) and (c)

both (b) and (c)

A fluid whose apparent viscosity increases with shear rate is termed as the __________ fluid. Newtonion viscous dilatant non-viscous

dilatant

Which of the following is the most common pump for pumping either raw sewage or sludge ? Electromagnetic pump Centrifugal pump Reciprocating pump Gear pump

Reciprocating pump

Transition length for a turbulent fluid entering into a pipe is around __________ times the pipe diameter. 5 50 500 1000

For turbulent flow of an incompressible fluid through a pipe, the flow rate Q is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent 'n' is 1 0 < 1 > 1

< 1

Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have very low speeds. smaller discharge. higher capital &maintenance cost. high vibrations.

higher capital &maintenance cost.

Which is the correct relationship for a centrifugal pump ? (where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) D = 1840 H^0.5/N D = 1840 N/H^0.5 H = 1840 D^0.5/N D = 1840 H/N

D = 1840 H^0.5/N

Which of the following pipe bends will incur the largest head loss ? U-bend 30° bend 45° bend 90° bend

U-bend

Which is the most efficient and best for measuring very small flow rate of gases ? Venturimeter Orifice meter Rotameter Flow nozzle

Rotameter

When the water is warm, the height to which it can be lifted by a pump decreases due to reduced viscosity. decreases due to reduced vapour pressure. increases due to increased vapour pressure decreases due to increased frictional resistance.

decreases due to reduced vapour pressure.

Pipes having diameter 14 inches or more are designated by their outside diameter inside diameter schedule number none of these

outside diameter

Viscosity of water at 40°C lies in the range of 1 x 10-3 to 2 x 10-3 kg/m.s 0.5 x 10-3 to 1 x 10-3 kg/m.s 1 to 2 kg/m.s 0.5 to 1 kg/m.s

0.5 x 10-3 to 1 x 10-3 kg/m.s

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute. 500 200 1000 750

500

The dimension of kinematic viscosity is ML-2T-1 L2T-1 ML-2T-2 none of these

L2T-1

A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the average velocity of water flowing through the main pipe is 5 m/sec, the average velocity through the bifurcated pipes is 20 m/sec 10 m/sec 5√2 m/sec 5 m/sec

10 m/sec

Turbulent flow generally occurs for cases involving highly viscous fluid very narrow passages very slow motion none of these

none of these

Lower BWG means __________ of the tube. lower thickness lower cross-section outer diameter inner diameter

lower cross-section

For laminar flow of Newtonion fluid in a circular pipe, the velocity distribution is a function of the distance 'd' measured from the centre line of the pipe, and it follows a __________ relationship. logarithmic parabolic hyperbolic linear

parabolic

The Prandtl mixing length is zero at the pipe wall and is a universal constant. independent of radial distance from the pipe axis. independent of the shear stress. useful for computing laminar flow problems.

useful for computing laminar flow problems.

Re^2/Fr is called the __________ number. Brinkman Galileo Archimedes Euler

Galileo

The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which "sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis". The centre of pressure of a rectangular surface (of width 'w') immersed vertically in a static mass of fluid is at a depth of(where, y = depth of the liquid) 1/(y/3) 2y/3 1/(y/4) 3y/4

2y/3

As the velocity V and thus the Reynolds number of a flow past a sphere increases from very low value, the drag force for Re << 1 increases linearly with V. decreases linearly with V. decreases as V2. none of these.

increases linearly with V.

Self-priming centrifugal pump can be used for booster service. pumping liquid fertilisers (e.g. liquid NH3). pumping industrial wastes. all (a), (b) and (c).

all (a), (b) and (c).

Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve. The extent of pressure thus produced due to water hammer depends on the pipe length fluid velocity in the pipe time taken to close the valve all (a), (b) and (c)

all (a), (b) and (c)

Bernoull's equation does not apply to the functioning of a/an venturimeter orificem pitot tube none of these

none of these

What is the shear rate at the pipe wall, in case of laminar flow of Newtonion fluids in a pipe of diameter 'D' & length 'L' incurring a pressure drop 'Δp' with average velocity 'Vavg'? D Δp/8L D Δp/4L 8 * Vavg/D 4 * Vavg/D

8 * Vavg/D

Pascal's law is valid, only when the fluid is frictionless and at rest. at rest. at rest and when the frictionless fluid is in motion. none of these.

at rest.

A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit (E) to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062. 10 m 11 m 12 m 20 m

11 m

The pressure head of a flow meter remains constant for venturimeter orificemeter rotameter pitot tube

rotameter

A venturimeter can not be used for the direct measurement of datum difference in the stretch of pipeflow pressure difference in the flow throughpipeline. friction loss in pipe flow. all (a), (b) and (c).

all (a), (b) and (c).

A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double _____. head discharge efficiency none of these

discharge

Which of the following is used for very accurate measurement of flow of gas at low velocity ? Pitot tube Rotameter Segmental orificemeter Hot wire annemometer

Hot wire annemometer

The rate of shear versus the shear stress curves are time dependent for __________ fluid. thixotropic rheopectic both (a) & (b) neither (a) nor (b)

both (a) & (b)

In Newton's law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is 0.44 0.044 4.4 44

0.44

A pressure of 10 m head of water is equivalent to __________ kN/m2. 98 147 196 49

A pressure head of 320 metres of water in meters of CCl4 (sp.gr = 1.6) will be 100 200 320 160

200

The ratio of the wall drag to the form drag in the Stoke's law range (for motion of spherical particles in a stationary fluid) is 0.5 1 2 0.33

For turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance 'd' measured from the wall of the pipe and the friction velocity 'v', and it follows a __________ relationship. logarithmic linear hyperbolic parabolic

logarithmic

Maintenance cost of a __________ pump for a particular duty is the least. centrifugal reciprocating volute gear

centrifugal

Choking in case of pipe flow means that a _____. specified mass flow rate can not be achieved. valve is closed in the line. restriction in flow cross-section area occurs. none of these.

specified mass flow rate can not be achieved.

Velocity of liquid hydrocarbon fuels in a pipeline can not be measured by magnetic flowmeters, because their __________ is very low/small. thermal conductivity electrical conductivity specific gravity electrical resistivity

electrical conductivity

The nominal size of a hose pipe is specified by its I.D. O.D. thickness none of these

I.D.

Transition from laminar flow to turbulent flow is aided by the surface roughness and curvature (i.e.sharp corners). vibration. pressure gradient and the compressibility of the flowing medium. all (a), (b) & (c).

all (a), (b) & (c).

For flow of fluids through packed bed, the superficial velocity is less than the average velocity through channels. more than the average velocity through channels. dependent on the pressure drop across the bed. same as the average velocity through channels.

less than the average velocity through channels.

Cd is always __________ Cc. greater than less than equal to either more or less than

greater than

Buoyant force for non-symmetrical bodies is not vertical. depends on the depth of the submergence of the floating body. depends on the weight of the floating body. none of these.

depends on the weight of the floating body.

Which of the following is an undesirable property of a manometric liquid ? Non-sticky & non-corrosive nature. High vapour pressure. Low viscosity & surface tension. Low co-efficient of thermal expansion.

High vapour pressure.

Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head. manometric total static friction

manometric

The speed of sound in an ideal gas varies as the temperature pressure density none of these

temperature

The maximum head that can be developed by a single impeller is __________ ft. 25 100 250-300 1000

250-300

The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is < 1 1 > 1 2

< 1

The general relationship between speed N, head H, power P and discharge Q for a centrifugal pump is Q∝N : H∝N^2 : P∝N^3 Q∝N^2 : H∝N^3 : P∝N Q∝N : H∝N^3 : P∝N^2 Q∝N^3 : H∝N : P∝N^2

Q∝N : H∝N^2 : P∝N^3

What is the ratio of the velocity at the axis of the pipe to the mean velocity of flow in case of pipe flow under viscous condition ? 0.5 0.67 1 2

Foot valve provided in the pump is a __________ valve. direction control back pressure relief pressure reduction

back pressure

The discharge co-efficient for an orificemeter does not depend upon the pipe length. ratio of pipe diameter to orifice diameter. type of orifice & the Reynolds number. pipe diameter.

pipe length.

Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump? Increasing the impeller speed and the volute area. Increasing the number of vanes in the impeller. Mounting of two or more impellers in series on a single shaft. Either of (a), (b) or (c).

Mounting of two or more impellers in series on a single shaft.

An equipotential line is __________ to the velocity vector at every point. normal abnormal tangential none of these

normal

Specific speed for a centrifugal pump is N√Q/H^3/4 N√Q/H^2/3 N^3D^5/H^1/3 N√Q/H

N√Q/H^3/4

Path followed by water jet issuing from the bottom of a water tank will be a parabola (vertex being at the opening). hyperbola. horizontal straight line. zig-zag path (which is geometrically undefined).

parabola (vertex being at the opening).

Which of the following produces maximum pressure difference for transportation of gases ? Vaccum pumps Blowers Fans Compressors

Compressors

For flow through a venturi at a particular discharge, the correct relationships among velocities at point X, Y and Z would be V1 < V2 < V3 V2 > V1 and V2 > V3 V1 > V2 > V3 none of these.

V2 > V1 and V2 > V3

Drag co-efficient in hindered settling is __________ that in free settling. less than equal to not necessarily greater than always greater than

always greater than

Efficiency of power transmission (η) through a circular pipe is given by (ht - hf)/ht, which has a maximum value of __________ percent. 33:3 50 66.6 88.8

66.6

One dimensional fluid flow implies the flow in straight lines only. uniform flow. steady uniform flow. flow in which transverse components are zero.

flow in which transverse components are zero.

__________ forces act on a particle moving through a stationary fluid. Gravity Drag Buoyant all (a), (b), & (c)

all (a), (b), & (c)

In frictional fluid flow, the quantity, P/ρ + V2/2gc + gz/gc, is constant along a streamline. not constant along a streamline. increased in the direction of flow. none of these.

not constant along a streamline.

Hydraulic radius is the ratio of wetted perimeter to flow area. flow area to wetted perimeter. flow area to square of wetted perimeter. square root of flow area to wetted perimeter.

flow area to wetted perimeter.

The unit of bulk modulus of elasticity for a liquid in S.I. unit is N N/m N/m2 N/m3

N/m2

Power requirement of fans having constant wheel diameter varies __________ fan speed. as square of directly as as cube of none of these

as cube of

In the low Reynolds number region, the drag force on a sphere is proportional to V V2 V4 V0.5

The continuity equation is independent of the compressibility of the fluid. is dependent upon the viscosity of the fluid. represents the conservation of mass. none of these.

represents the conservation of mass.

Experimental study of laminar fluid flow through a circular tube was conducted by Reynolds Hagen and Poiseuille Pascal Blake-Plummer

Hagen and Poiseuille

The most economical flow control valve for use with large diameter pipes is a butterfly valve globe valve needle valve none of these

butterfly valve

Each term in Bernaulli's equation represents the __________ of the fluid. energy per unit mass energy per unit weight force per unit mass none of these

energy per unit weight

Which of the following is a dimensionless parameter ? Angular velocity Specific weight Kinematic viscosity None of these

None of these

If the head over the triangular notch is doubled, the discharge will increase by __________ times. 2 2.828 5.657 4

5.657

Friction factor for a hydraulically smooth pipe at NRe = 2100 is f1. If the pipe is further smoothened (i.e., roughness is reduced), the friction factor at the same value of NRe, will increase. decrease. remain unchanged. increase or decrease depending on the pipe material.

increase

What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water iterface? The balloon is of radius 0.1 m and is filled with air. 4ng/3 0.01ngH/4 0.01ngH/8 0.04ngH/3

4ng/3

For the laminar flow of a fluid in a circular pipe of radius R, the Hagen-Poisseule equation predicts the volumetric flow rate to be proportional to R R^2 R^4 R^0.5

R^4

Interstage coolers are provided in a multistage compressor to save power in compressing a given volume to a given pressure. cool the delivered air. achieve the exact delivery pressure. none of these.

save power in compressing a given volume to a given pressure.

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases. NPSH required. BHP required by the pump. head of the liquid pumped. all (a), (b) and (c).

all (a), (b) and (c).

Reynolds number is the ratio of viscous forces to gravity forces. inertial forces to viscous forces. viscous forces to inertial forces. inertial forces to gravity forces.

inertial forces to viscous forces.

For the manometer set up shown in the figure, the pressure difference PA - PB is given by (ρH - ρair)gH (ρH - ρL)gH (ρH - ρL) gH + (ρL - ρair) . g(L - H) (ρH - ρL) gL + (ρL - ρair)gH

(ρH - ρair)gH

The discharge through a venturimeter depends upon pressure drop only. its orientation. co-efficient of contraction only. none of these.

pressure drop only.

N. second/m2 is the S.I. unit of dynamic viscosity. the S.I. unit of kinematic viscosity. equivalent to one poise. equivalent to one stoke.

the S.I. unit of dynamic viscosity.

The distance between metacentre and __________ is called metacentric height. water surface centre of gravity centre of buoyancy none of these

centre of gravity

Check valve is used for __________ flow. very precise control of unidirectional multidirectional none of these

unidirectional

Capacity of a rotary gear pump can be varied by changing the speed of rotation. bleeding air into suction. bypassing liquid from the suction or discharge line. all (a), (6) and (c).

all (a), (6) and (c).

For a given Reynolds number, in a hydraulically smooth pipe, further smoothening __________ the friction factor. brings about no further reduction of increases decreases none of these

brings about no further reduction of

Power number is the ratio of drag stress to inertial stress. inertial stress to drag stress. inertial stress to gravitational stress. gravitational stress to drag stress.

drag stress to inertial stress.

The momentum correction factor for the velocity distribution of laminar flow is 1.3 1.66 2.5 none of these

none of these

For the same flow rate of a fluid, the pressure drop is the least for venturimeter orificemeter flow-nozzle Δp is same for all

venturimeter Venturimeter < Flow nozzle < Orificemeter

The valve commonly used in pipes larger than 2" dia is a globe valve plug-cock gate valve check valve

gate valve

Foot valves are provided in the suction line of a centrifugal pump to avoid priming, every time we start the pump. remove the contaminant present in the liquid. minimise the fluctuation in discharge. control the liquid discharge.

avoid priming, every time we start the pump.

An ideal fluid is frictionless & incompressible. one, which obeys Newton's law of viscosity. highly viscous. none of these.

frictionless & incompressible.

In area meter (e.g., rotameter), with increase in the fluid flow rate, the pressure drop increases linearly. pressure drop is almost constant. area through which fluid flows does not vary. none of these.

pressure drop is almost constant.

Drag co-officient CD, in Stoke's law range is given by Cd = 16/Re Cd = 24/Re Cd = 18.4/Re Cd = 0.079/Re^0.25

Cd = 24/Re

In power law, ζ = A(du/dy)^2 +B, then the fluid is ____. Newtonian dilatant thixotropic rheopectic

Newtonian

The buoyant force acting on a floating body is dependent on the viscosity of the liquid. weight of the liquid displaced. depth of immersion of the body. surface tension of the liquid.

weight of the liquid displaced.

A Newtonion fluid is that which follows Newton's law of motion. which needs a minimum shear, before it starts deforming. for which shear & deformation are related as Τ = μ*ϑu/ϑy none of these.

for which shear & deformation are related as Τ = μ*ϑu/ϑy

In case of end to end connection of two or more pipes in series, the __________ each pipe. same rate of flow passes through head loss is same through rate of flow in each pipe is proportional to the length of total flow rate is the sum of flow rate in

same rate of flow passes through

Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ? Fanning equation Blake-Pllummer equation Hagen-Poiseulle equation Kozney-Karman equation

Blake-Pllummer equation

The flow of gas along a pipe in the direction of decreasing pressure causes decrease in its viscosity specific volume velocity none of these

specific volume

Centrifugal pump can't be used to pump molten sodium (used as a coolant in Fast Breeder Reactor). moderately viscous vegetable oil used in soap industry. thick molten soap at 80°C. none of the above.

thick molten soap at 80°C.

A stream line is fixed in space in steady flow. always the path of particle. drawn normal to the velocity vector at every point. a line connecting the mid points of flow cross-section.

fixed in space in steady flow.

Quicksand is an example of a __________ fluid. bingham plastic dilatent Newtonion pseudoplastic

dilatent

Correction for capillary effect in manometers (used for pressure measurement) need not be applied, if diameter of the manometer tube is __________ mm. < 4 > 4 > 12.5 < 10

> 12.5

Differential manometer measures the absolute pressure gauge pressure pressure difference pressure gradient

pressure difference

The pressure and power requirement of a gas fan at constant speed & capacity varies __________ the gas density. directly as inversely as square root of inversely as as square of

directly as

Isothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the wall roughness. Reynolds number. both (a) & (b). neither (a) nor (b).

both (a) & (b).

Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.) √d d^1/3 d^2 d^2/3

√d

Gradually varied flow in open channel is a/an __________ flow. steady uniform steady non-uniform unsteady uniform unsteady non-uniform

steady non-uniform

The line of action of the buoyant force acts through the centroid of the displaced volume of fluid. centre of gravity of a submerged body. centroid of the volume of any floating body. none of these.

centroid of the displaced volume of fluid.

Cavitation in a centrifugal pump can be avoided by keeping the inlet pressure high outlet pressure low inlet pressure low outlet pressure high

inlet pressure high

Vane anemometer is an area meter. is a variable head meter. rotates an element at a speed determined by the velocity of the fluid in which the meter is immersed. none of these.

rotates an element at a speed determined by the velocity of the fluid in which the meter is immersed.

The peripherial velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec. 1.8 12.4 186.2 736.4

12.4

Laminar flow is characterised by the nonexistence of pressure fluctuation. eddies. deviating velocities. all (a), (b)&(c).

all (a), (b)&(c).

The length of the tube necessary for the boundary layer to reach the centre of the tube and for fully developed flow to be established is called the __________ length. equivalent transition Prandtl mixing none of these

transition

Select the correct practical example of steady non-uniform flow. Motion of water around a ship in a lake. Motion of river around bridge piers. Steadily decreasing flow through a reducing section. Steadily increasing flow through a pipe.

Steadily decreasing flow through a reducing section.

Hydraulic diameter for non-circular ducts is equal to __________ times the area of flow divided by the perimeter. two three four eight

four

Terminal velocity is a constant velocity with no acceleration. a fluctuating velocity. attained after moving one-half of total distance. none of these

a constant velocity with no acceleration.

Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement. f1 = f2 f1 < f2 f1 > f2 data not sufficient to relate f1 & f2

f1 > f2

For an incompressible fluid, the bulk modulus of elasticity is 5 kg/m3 ∞ N/m2 1 N 0 N/m

∞ N/m2

A fluid is a substance, that has to be kept in a closed container. is almost incompressible. has zero shear stress. flows when even a small shear is applied to it.

flows when even a small shear is applied to it.

The pressure intensity is the same in all directions at a point in a fluid only when the fluid is frictionless. only when the fluid is at rest having zero velocity. when there is no motion of one fluid layer relative to an adjacent layer. regardless of the motion of one fluid layer relative to an adjacent layer.

when there is no motion of one fluid layer relative to an adjacent layer.

Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newton's law of viscosity. (II) Newton's second law of motion. (III) The continuity equation. (IV) Velocity of boundary layer must be zero relative to boundary. (V) Fluid cannot penetrate a boundary. I, II, III II, III, V I, II, V II, IV, V

II, III, V

. Mach number is defined as the ratio of the local flow velocity to the sonic velocity in the fluid. For what value of Mach number, the gases are considered incompressible ? < 0.3 > 3 50 1

< 0.3

Boundary layer exists in flow ____. of real fluids. over flat surfaces only. in pipes only. of ideal fluids only.

of real fluids.

Rubber latex is an example of __________ fluid. dilatent Newtonion pseudoplastic Bingham plastic

pseudoplastic

Velocity head on sudden enlargement in a horizontal pipe is converted into __________ head. elevation pressure both (a) & (b) neither (a) nor (b)

pressure

The frictional resistance in laminar flow does not depend on the area of surface in contact. flow velocity. fluid temperature. pressure of flow.

area of surface in contact.

A venturimeter measures the velocity head pressure point velocity none of these

none of these

Gradually varying fluid flow is an example of __________ flow. non-steady uniform non-steady non-uniform steady uniform steady non-uniform

non-steady uniform

Drag is the force component exerted on an immersed object, passing the centroid of the body at 60°to the direction of motion. the component being parallel to theflow direction. the component being normal to the flow direction. none of these.

the component being parallel to theflow direction.

To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump. reciprocating centrifugal volute rotary vacuum

reciprocating

Cocks are used to control water any liquid solids none of these

any liquid

The dimension of surface tension is ML-2 MT-2 MLT-2 ML-2T

MT-2

Pick out the correct statement. Fanning friction factor is inversely proportional to Reynolds number always. The property of a randomly packed bed (with raschig rings) is given by the ratio of the total volume to the volume of voids in the bed. Mach number in an incompressible fluid is always unity. Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow.

Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow.

The friction factor is always inversely proportional to the Reynolds number. not dimensionless. not dependent on the roughness of the pipe. none of these.

none of these.

Rubber latex is an example of a __________ .fluid. pseudoplastic bingham plastic dilatent Newtonion

pseudoplastic

Which of the following factors does not contribute to the pressure drop in a pipeline ? Velocity of fluid Size of pipe Length of pipe and number of bends None of these

None of these

The phenomenon occuring during pumping of a liquid solution containing dissolved gases, which may come out of the solution giving rise to gas pockets, is termed as evaporation cavitation sublimation stripping

cavitation

Working of a __________ pump characterises mixed flow. turbine piston diaphragm none of these

turbine

The equivalent diameter for pressure drop calculation for a fluid flowing through a rectangular cross-section channels having sides 'x' & 'y' is given by ____. 2xy/x+y xy/x+y x+y/2xy x+y/xy

2xy/x+y

The rate of change of moment of momentum represents the __________ by the fluid. torque applied force exerted work done power developed

torque applied

Cd for the orifice plate varies from 0.58 to 0.8 0.93 to 0.98 0.2 to 0.3 0.02 to 0.03

0.58 to 0.8

The discharge through a V-notch weir varies as H^3/2 H^1/2 H^5/2 H^2/3

H^5/2

Water flow rate in a pipe of 3.5 metres diameter can be most economically and conveniently measured by a/an pitot tube venturimeter orificemeter rotameter

pitot tube

The specific speed of a pump is defined as the speed of a unit of such a size, that it delivers unit discharge at unit head. requires unit power for unit head. delivers unit discharge at unit power. none of these.

delivers unit discharge at unit head.

In case of venturimeters, friction losses are about __________ percent of maximum velocity head. 2 8 12 20

With increase in the schedule number of a pipe of a particular nominal size, the wall thickness also increases. I.D. of the pipe decreases. O.D. of the pipe remains constant. all (a), (b) and (c)

all (a), (b) and (c)

Turbine impeller produces only radial current. produces only tangential current. is effective over wide range of viscosities. does not produce tangential current.

is effective over wide range of viscosities.

Friction produced by the formation of wakes is called the __________ friction. disk skin form none of these

form

Various efficiencies of a centrifugal pump are related as (where, ηm = mechanical efficiency ηv = volumetric efficiency. ηma = manometric efficiency ηo = overall efficiency) ηma x ηm x ηv = ηo ηm = ηv . ηma ηma = ηm x ηv ηv = ηm x ηma

ηm = ηv . ηma

When the pipe Reynold's number is 6000, the flow is generally viscous laminar turbulent transition

turbulent

With a constant diameter impeller of a centrifugal pump its capacity varies directly as the square of speed. head varies as the square of speed. horsepower input varies as the square of speed. head varies as the speed.

head varies as the square of speed.

For water, when the pressure increases, the viscosity also increases decreases remains constant first decreases, and then increases

first decreases, and then increases

The head loss due to sudden expansion is v1^2-v2^2/2gc (v1-v2)^2/2gc v1-v2/2gc v1^2-v2^2/gc

(v1-v2)^2/2gc

Location of vena-contracta in an orificemeter does not depend upon the type of orifice. density, viscosity & compressibility of the fluid. ratio of pipe diameter to orifice diameter. pipe roughness.

type of orifice.

At low Reynolds number viscous forces are unimportant. viscous forces control. viscous forces control and inertial forces are unimportant. gravity forces control.

viscous forces control and inertial forces are unimportant.

For laminar flow through a closed conduit Vmax = 2Vav Vmax = Vav Vmax = 1.5Vav Vmax = 0.5Vav

Vmax = 2Vav

In Newton's law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass varies as the __________ of its diameter. inverse square root second power first power

square root

Unsteady uniform flow is represented by flow through a/an long pipe at constant rate. long pipe at decreasing rate. expanding tube at increasing rate. expanding tube at constant rate.

long pipe at decreasing rate.

If Blausius or Darcey friction factor is 'f1' then the Fanning friction factor is equal to f1/4 4f2 2f1 f1/2

f1/4

Pick out the wrong statement pertaining to fluid flow. The ratio of average velocity to the maximum velocity for turbulent flow of Newtonion fluid in circular pipes is 0.5. The Newtonion fluid velocity in a circular pipe flow is maximum at the centre of the pipe. Navier-Stokes equation is applicable to the analysis of viscous flows. Hagen-Poiseuille equation is applicable to the laminar flow of Newtonion fluids.

The ratio of average velocity to the maximum velocity for turbulent flow of Newtonion fluid in circular pipes is 0.5.

A Newtonion liquid (ρ = density, μ = viscosity) is flowing with velocity v in a tube of diameter 'D'. Let Δp be the pressure drop across the length 'L'. For a laminar flow, Δp is proportional to L ρv2/D L μ;V/D2 D ρv2/L μ V/L

L ρv2/D

While starting a centrifugal pump, its delivery valve should be kept opened. closed. either opened or closed ; it does not make any difference. either opened or closed; depending on the fluid viscosity.

closed.

For flow past a flat plate, if x is the distance along the plate in the direction of flow, the boundary layer thickness is proportional to √x 1/√x x 1/x

√x

Velocity at a certain point in case of streamline flow is constant independent of time both (a) & (b) neither (a) nor (b)

both (a) & (b)

Sewage sludge is an example of the __________ fluid. Bingham plastic Newtonion pseudoplastic dilatent

Bingham plastic

In case of a rotameter, the density of the float material is __________ that of the liquid it replaces. more than less than equal to either (a) or (b)

more than

Multistage centrifugal pumps are generally used for high head. low head but high discharge. highly viscous liquid. slurries of high solid concentration.

high head.

The fluid jet discharging from a 2" diameter orifice has a diameter of 1.75" at its vena-contracta. The co-efficient of contraction is 1.3 0.766 0.87 none of these

0.766

A bed consists of particles of density 2000 kg/m3. If the height of the bed is 1.5 metres and its porosity 0.6, the pressure drop required to fluidise the bed by air is 25.61 kPa 11.77 kPa 14.86 kPa 21.13 kPa

11.77 kPa

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ? Decrease in effect Increase in thrust Develops noise Develops high pressure

Develops high pressure

For a specific centrifugal air blower operating at constant speed & capacity, the power requirement and pressure vary directly as square of gas density. directly as gas density. directly as square root of gas density. inversely as gas density

directly as gas density.

Capillary tube method of viscosity measurement is based on the Hagen-Poiseulle's equation Stoke's law Navier-stokes equation none of these

Hagen-Poiseulle's equation

It is possible to integrate an automatic flow controller to a flow nozzle venturimeter rotameter none of these

rotameter

For liquid flow through a packed bed, the superficial velocity as compared to average velocity through the channel in the bed is more less equal independent of porosity

less

For a reciprocating pump, the indicator diagram is the graph between the discharge and overall efficiency. volume swept by piston for one complete revolution and the pressure in the cylinder. angle swept by the crank pin at any instant and the discharge. none of these.

volume swept by piston for one complete revolution and the pressure in the cylinder.

The most important factor, which determines the maximum height to which water can be lifted by a pump at standard temperature is the barometric pressure speed of the impeller diameter of the impeller both (b) and (c)

barometric pressure

High specific speed of a pump implies that, it is a/an __________ pump. centrifugal mixed flow axial flow none of these

axial flow

A gas (density = 1.5 kg/m3 , viscosity = 2x 10-5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5kg/m3and viscosity of 3 x 10-5kg/m.s flowing at 3 m/s will be 8400 Pa/m 12600 Pa/m 18900 Pa/m 16800 Pa/m

12600 Pa/m

One poise (unit of absolute/dynamic viscosity) is equivalent to one gm/cm2. sec. gm/cm. sec. cm2/sec. m2/sec.

gm/cm. sec.

The equation relating friction factor to Reynold number, f-0.5 = 4 loge (NRe/f)-0.4, is called the __________ equation. Nikuradse Von-Karman Blausius Colebrook

Nikuradse

Pressure drop for turbulent fluid flow through a circular pipe is given by 64/Re 32μLV/gc*D^2 4f*(L/D)*(v^2/2gc)*ρ f*(L/D)*(v^2/2gc)*ρ

4f*(L/D)*(v^2/2gc)*ρ

What is the co-efficient of contraction, if a fluid jet discharging from a 50 mm diameter orifice has a 40 mm diameter at its vena-contracta ? 0.64 1.65 0.32 0.94

0.64

For an unstable equilibrium of a floating body (where, M = metacentre.) M is above G M is below G M & G coincide none of these

M is below G

Which of the following can be used for the direct measurement of volumetric flow rate of slurry ? Venturimeter Orificemeter Rotameter Pitot tube

Rotameter

A pipe is defined as 'hydraulically smooth', if the friction factor is not a function of Reynolds number. for a given Reynolds number remains constant even on further smoothening of the pipe. is zero irrespective of the Reynolds number. none of these.

for a given Reynolds number remains constant even on further smoothening of the pipe.

A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is 5 14.1 56.22 28.2

28.2

Delivery of insufficient quantity of liquid by a pump may be caused by air leak in the inlet low rpm too high a lift all (a), (b) and (c)

all (a), (b) and (c)

Fluid resistance to shear depends upon its rate of transfer of molecular momentum. cohesion. both (a) and (b). neither (a) nor (b).

both (a) and (b).

In case of a __________ the energy of flow is considerably decreased downstream of the machine. blower turbine centrifugal pump centrifugal fan

turbine

With increase in the shear rate, the apparent viscosity of pseudoplastic fluids increases decreases remains same may increase or decrease; depends on the magnitude of shear rate

decreases

Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about 0.42 0.62 0.82 0.98

0.62

Purpose of hydraulic accumulator is to ensure intermittant supply of hydraulic pressure. increase the pressure and store/ accumulate it. accumulate pressure to increase force. generate high pressure to operate hydraulic machines like cranes, lifts, presses etc

generate high pressure to operate hydraulic machines like cranes, lifts, presses etc

Pick out the wrong statement. Surface tension of a liquid is because of the difference in magnitude of adhesive & cohesive forces. A hydrometer used for the determination of specific gravities of liquids works on the principle of buoyant forces. In case of unsteady fluid flow, the velocity at any given point does not change with time. Turbulent fluid flow is characterised by the rapid fluctuation of instantaneous pressure & velocity at a point.

In case of unsteady fluid flow, the velocity at any given point does not change with time. It does change in time.

Purpose of relief valve in a reciprocating pump is to protect the pump against developing excessive pressure. facilitate unidirectional flow of liquid. reduce the discharge pressure. control the rate of discharge.

protect the pump against developing excessive pressure.

Select the correct statement. The discharge through a venturimeter depends upon Δp only and is independent of orientation of the meter. A venturimeter with a given gage difference discharges at a greater rate, when the flow is vertically downward through it, than when the flow is vertically upward. For a given pressure difference, the discharge of gas is greater through a venturimeter, when compressibility is taken into account, than when it is neglected. The overall pressure loss is the same in a given pipe line, whether a venturimeter or a nozzle with the same throat dia is used.

The discharge through a venturimeter depends upon Δp only and is independent of orientation of the meter.

The Kozney-Carman equation, rewritten in terms of non-dimensional numbers gives (ΔP/pu2 ) proportional to L/Dp/Re Re/Dp/L L/Dp/Re^2 Re^2/Dp/L

L/Dp/Re

In case of turbulent flow of fluid through a circular pipe, the mean flow velocity is about 0.5 times the maximum velocity. velocity profile becomes flatter and flatter with increasing Reynolds number. point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius). skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more.

skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more.

For the same terminal conditions and valve size, the pressure drop in a fully opened globe valve as compared to that in a gate valve is more less equal either (a) or (b); depends on the viscosity of the fluid

Steady fluid flow occurs, when the derivative of flow variables satisfy the following condition. ϑ/ϑs = 0 ϑ/ϑt = 0 ϑ/ϑs = constant ϑ/ϑt = constant

ϑ/ϑt = 0

What is the maximum theoretical suction lift (metres) of a reciprocating pump ? 5 10 50 100

The terminal velocity of a particle moving through a fluid varies as dpn. The value of n is equal to __________ in Stoke's law regime. 1 0.5 2 1.5

Function of air vessel provided in a reciprocating pump is to reduce discharge fluctuation. reduce the danger of cavitation. avoid the necessity of priming. increase the pump efficiency.

reduce discharge fluctuation.

The Prandtl pitot tube measures the velocity at a point in the flow. pressure at a point. average flow velocity. pressure difference in pipe flow.

velocity at a point in the flow.

Pressure drop in packed bed for turbulent flow is given by the __________ equation. Kozney-Karman Blake-Plummer Leva's Hagen-Poiseulle's

Blake-Plummer

In the complete turbulence zone (in rough pipes), the rough and smooth pipes have the same friction factor. laminar film covers the roughness projections. friction factor depends upon NRe only. friction factor is independent of the relative roughness.

friction factor is independent of the relative roughness.

Which of the following has the minimum compressibility ? Water at room temperature Air at room temperature Oxygen at room temperature Nitrogen at room temperature

Water at room temperature

In case of centrifugal fan or blower, the gas capacity varies as speed (speed)2 (speed)3 (speed)0.5

speed

Pick out the wrong statement. A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocity. Newton's law of viscosity is not applicable to the turbulent flow of fluid with linear velocity distribution. Laminar flow of viscous liquids is involved in the lubrication of various types of bearings. Rise of water in capillary tubes reduces with the increasing diameter of capillary tubes.

Newton's law of viscosity is not applicable to the turbulent flow of fluid with linear velocity distribution.

Pick out the wrong statement. In a static mass of liquid, the pressure at a point is the same for all liquids. Pressure decreases exponentially with elevation in an isothermal atmosphere. Atmospheric pressure = absolute pressure-gage pressure. As per Pascal's law, the pressure at a point in a static or uniformly moving fluid is equal in all directions.

In a static mass of liquid, the pressure at a point is the same for all liquids.

The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is parabolic flat flat near the wall and parabolic in the middle parabolic near the wall and flat in the middle.

parabolic near the wall and flat in the middle.

Fanning friction factor for laminar flow of fluid in a circular pipe is not a function of the roughness of pipe wall. inversely proportional to Reynolds number. both (a) & (b). neither (a) nor (b).

both (a) & (b).

Mach number is the ratio of the speed of the fluid to that of the light. light to that of the fluid. fluid to that of the sound. sound to that of the fluid.

fluid to that of the sound.

piezometer opening measures the __________ fluid pressure. static undisturbed total dynamic

undisturbed

Drag force on the float of a rotameter is(where Q = flow rate of the ) ∝Q ∝Q ∝Q2 constant

constant

The unit of dynamic viscosity in SI unit is kg/m . sec N/m2 m2 /sec. m/N. sec.

kg/m . sec

Pressure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as V^1.8 V^-0.2 V^2.7 V^2

V^2

Dean number is concerned with the fluid-particle interaction. fluid flow through helical pipes. power consumption in agitated vessels. psychrometry.

fluid flow through helical pipes.

The equation given below is called the __________ . f-0.5 = 4.07 loge (NRef)-0.6 Colebrook formula Von-Karman equation Fanning equation none of these

Von-Karman equation

Poise is converted into stoke by multiplying with density (gm/c.c). dividing by density (gm/c.c). multiplying with specific gravity. dividing by specific gravity.

dividing by density (gm/c.c).

The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop fo __________ fluid. dilatant pseudoplastic Bingham plastic Newtonion

dilatant

Kinetic energy of fluid per unit weight represented by the velocity head is given by 2v2/gc v2/2gc ρv2/gc ρ.v2/2gc

v2/2gc

At a constant speed of the centrifugal pump . it __________ the impeller diameter. capacity varies directly with head varies as the square of horsepower varies as the cube of all (a), (b) and (c)

all (a), (b) and (c)

The pressure co-efficient is the ratio of pressure forces to __________ forces. viscous inertial gravity surface tension

viscous

Vena-contracta formed during flow of a liquid through an orificemeter has minimum liquid cross-section. more diameter compared to orifice diameter. minimum velocity of fluid stream. none of these.

minimum liquid cross-section.

As per Newton's law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to(where, μ = fluid viscosity) 1/μ μ μ^2 1/μ^2

Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will __________ the gas discharge pressure. increase decrease not change exponentially decrease

increase

In continuous fluidisation solids are completely entrained. the pressure drop is less than that for batch fluidisation. there is no entrainment of solids. velocity of the fluid is very small.

solids are completely entrained.

Glass pipes can be joined by flanges welding soldering bell and spigot joint

bell and spigot joint

If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is same in both the tubes. greater in 1 mm dia tube. greater in 0.5 mm dia tube. zero in both the tubes.

greater in 0.5 mm dia tube.

For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of 2 <2 >2 1/2

Weber number is the ratio of inertial force to __________ force. surface tension gravity viscous elastic

surface tension

The curve of metacentre for a floating body __________ the curve of buoyancy. is always below is the evolute of intersects at right angle is tangential to

is the evolute of

At what value of crank angle (roughly), no flow of water from or into the air vessel takes place in case of a double acting reciprocating pump ? 40° and 140° 45° and 60° 90° and 80° 20° and 120°

40° and 140°

The range of a particular rotameter can be increased by use of floats of different densities. no means. increasing the diameter of the float. decreasing the diameter of the float.

use of floats of different densities.

Which of the following is dimensionless ? Angular velocity Fanning friction factor Specific volume None of these

Fanning friction factor

A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is __________ litres. 600 660 1.1 60

660

A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump. sump volute vacuum submerged

vacuum

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 x 103 VOM + 10.94 x 106 V2OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ? 0.2 0.5 0.7 0.8

0.7

Dimension of kinematic viscosity is MLT-1 L2 . T-1 L2T L2 . T-2

L2 . T-1

A streamline is a line in flow field, that is traced by all the fluid particles passing through a given point. along which a fluid particle travels. such that at every point on it, the velocity is tangential to it. none of these.

such that at every point on it, the velocity is tangential to it.

While starting an axial flow pump, its delivery valve should be kept open closed either open or closed none of these

closed

__________ forces do not act in case of fluid flow. Elastic Tensile Vibratory Centrifugal

Tensile

Non-colloidal solution is an example of the __________ fluid. non-Newtonion Newtonion dilatent pseudoplastic

Newtonion

Boundary layer separation is caused by the reduction of pressure below vapour pressure. reduction of pressure gradient to zero. adverse pressure gradient. reduction of boundary layer thickness to zero.

adverse pressure gradient.

Identification of pipelines carrying different liquids and gases is done by the __________ of the pipe. diameter colour altitude none of these

colour

Pick out the correct statement. Human blood is a Newtonion fluid. A Newtonion fluid obeys Newton's law of cooling. For a non-Newtonion fluid, a straight line passes through the origin in a plot between shear stress and shear gradient. Thin lubricating oil is an example of a non-Newtonion fluid.

A Newtonion fluid obeys Newton's law of cooling.

What is the unit of kinematic viscosity in SI unit ? M2/sec N/m2 . sec Kg . sec/m None of these

M2/sec

Hydraulic __________ works on the principle of Pascal's law of transmission of fluid pressure. press turbine pump coupling

press

A 2" gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Δp. For the same discharge, the pressure drop across globe valve is Δp < Δp > Δp Δp2

> Δp

The contraction co-efficient for Borda's mouthpiece (for frictionless fluid) is 0.1 0.5 0.94 1

0.5

Purpose of air lift pump is to compress air. lift compressed air. lift water from a well by using compressed air. lift air under negative pressure.

lift water from a well by using compressed air.

Pick out the correct statement pertaining to venturimeter. A venturimeter with a fixed pressure drop discharges more, when the flow is vertically downward, than when the flow is vertically upward. The co-efficient of contraction of a venturimeter is always unity. For a fixed pressure drop, the discharge of a gas through a venturimeter is greater, when compressibility is taken into account, than when it is neglected. none of these.

none of these.

For very low pressure and high discharge rate, the compressor used is a/an __________ compressor. axial reciprocating rotary none of these

rotary

Pumping of a corrosive liquid is generally preferred to be done by a __________ pump, as it can be made of a variety of materials including plastics. piston gear positive displacement sump

gear

The main factor on which the behaviour of a mass of fluidised solid depends mainly is the fluid characteristics particle size both (a) and (b) neither (a) nor (b)

both (a) and (b)

What is the speed of sound (m/sec) in ordinary water ? 1500 330 1000 3000

1500

Two piping system are said to be equivalent, when the __________ are same. fluid flow rate & friction loss length & friction factor diameter & friction factor length & diameter

fluid flow rate & friction loss

Potential function is applicable only for __________ flow. irrotational turbulent steady none of these

irrotational

Which of the following exemplifies a three dimensional fluid flow ? Fluid flow at the inlet to a nozzle Fluid flow between parallel plates Viscous fluid flow between converging plates None of these

Fluid flow at the inlet to a nozzle

Volute of a centrifugal pump should be designed in a fashion, such that the kinetic head gets converted into static head. moving stream gradually reduces velocity. mean velocity remains constant. none of these.

kinetic head gets converted into static head.

The head loss due to sudden contraction is proportional to velocity velocity head turbulence none of these

velocity head

Cavitation occurs in a centrifugal pump when the suction pressure is less than the vapour pressure of the liquid at that temperature. greater than the vapour pressure of the liquid at that temperature. equal to the vapour pressure. equal to the developed head.

less than the vapour pressure of the liquid at that temperature.

An ideal plastic substance indicates no deformation, when stressed upto yield stress, but behaves like a Newtonion fluid beyond yield stress. Which of the following is an ideal plastic ? Sewage sludge Rubber latex Blood Sugar solution

Sewage sludge

The capacity of a centrifugal pump Can be increased by increasing the impeller diameter or speed. number of pumps and joining them in series, number of pumps and joining them in parallel. all (a), (b) and (c).

all (a), (b) and (c).

Which law is followed by the velocity distribution in the turbulent boundary layer? Parabolic law Linear law Logarithmic law None of these

Logarithmic law

The losses in open channel flow generally vary as the inverse of the roughness. first power of the roughness. square of the velocity. inverse square of hydraulic radius.

first power of the roughness.

Rise of liquid in a capillary tube is due to cohesion adhesion both (a) & (b) neither (a) nor (b)

both (a) & (b)

Out of the following flow measuring devices, which one incurs the maximum installation cost as well as pressure loss ? Flow nozzle Venturimeter Rotameter Orificemeter

Venturimeter

For turbulent fluid flow in pipe, the expression for Prandtl one seventh power law is (where, r= pipe radius, x = distance). V/Vmax = (x/r)1/7 V/Vmax = (r/x)1/7 V/Vmax = (x.r)1/7 none of these

V/Vmax = (x/r)1/7

Which of the following has the maximum compression ratio ? Blower Compressor Vacuum pump Fan

Vacuum pump

Scale up of agitator design requires geometrical similarity only. dynamic similarity only. both geometrical and dynamic similarity. all geometrical, dynamic and kinematic similarity.

all geometrical, dynamic and kinematic similarity.

The actual velocity at vena-contracta for flow through an orifice from a reservoir is given by Cv . √2gH Cc . √2gH Cd . √2 * gH Cv . Va

Cv . √2gH

The head loss in turbulent flow in pipe is proportional to(where, V = velocity of fluid through the pipe) V^2 1/V^2 1/V V

V^2

Unsteady non-uniform flow is represented by flow through a/an long pipe at constant rate. long pipe at decreasing rate. expanding tube at increasing rate. expanding tube at constant rate.

expanding tube at increasing rate.

Prandtl number is a measure of the ____. heat conduction to viscosity of a fluid. Cp/Cv of a fluid. elastic force to pressure force in the fluid flow. inertial force to elastic force in the fluid flow.

heat conduction to viscosity of a fluid.

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres. 2 4 8 5.5

In hindered settling, the particles are placed farther from the wall. not affected by other particles and the wall. near each other, none of these.

near each other,

A globe valve is the most suitable for applications, in which fluid flow control is required. fluid contains dispersed solid particles. valve is required to be either fully open or fully closed. one way flow is required.

fluid flow control is required.

__________ isused for measuring the static pressure exerted on the wall by a fluid flowing parallel to the wall in a pipeline. Venturimeter Pressure gauge Pitot tube Orificemeter

Pitot tube

One stoke (unit of kinematic viscosity) is equivalent to 1 cm2/second 1 m2/second 1 gm/cm. second 1 kg . m/second

1 cm2/second

Air vessel of a reciprocating pump is initially filled with atmospheric air compressed air water none of these

compressed air

The ratio of inertial forces to gravity forces is called the __________ number. Mach Froude Euler Weber

Froude

Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m) N^2D^3 ND^2 N^2D N^3D^5

N^3D^5

Equivalent length of a pipe fitting is dependent on Reynolds number. independent of Reynolds number. dependent on the length of the pipe. none of these.

dependent on Reynolds number.

Buckingham-π theorem states that in any physical problem including 'n' quantities having 'm' diamensions, the quantities can be arranged into __________ independent dimensionless parameters. m n n-m n/m

n-m

A fluid which has a linear relationship between the magnitude of applied shear-stress and the resulting rate of deformation is called a/an __________ fluid. Newtonion Non-Newtonion ideal incompressible

Newtonion

Existence of boundary layer in fluid flow is because of the surface tension fluid density fluid viscosity gravity forces

fluid viscosity

In case of laminar flow of fluid through a circular pipe, the shear stress over the cross-section is proportional to the distance from the surface of the pipe. surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder. velocity profile varies hyperbolically and the shear stress remains constant over the cross-section. average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius).

surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder.

Which of the following facilitates close control of flow of fluids ? Gate valve Globe valve Butterfly valve Check valve

Globe valve

Fanning friction factor equation applies to the __________ fluid flow. non-isothermal condition of compressible both (a) and (b) neither (a) nor (b)

neither (a) nor (b)

For an ideal fluid flow, Reynolds number is 2100 100 0 ∞

∞

Stoke's equation is valid in the Reynolds number range 0.01 to 0.1 0.1 to 2 2 to 10 10 to 100

0.01 to 0.1

When a fluid flows over a solid surface, the velocity is uniform at any cross-section. velocity gradient is zero at the solid surface. resistance between the surface & the fluid is lesser as compared to that between the fluid layers themselves. velocity is not zero at the solid surface.

velocity gradient is zero at the solid surface.

Pick out the wrong statement about cavitation. Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation. Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities. Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise. Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades.

Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades.

The maximum delivery pressure of a reciprocating compressor may be about __________ kg/cm2. 1000 2000 3000 4000

4000

The velocity for subsonic flow in a pipeline increases in the downstream direction. is constant. decreases in the downstream direction. is independent of the area of flow.

increases in the downstream direction.

Permanent pressure loss in a well designed venturimeter is about __________ percent of the venturi differential. 1 10 30 50

The ratio of pressure forces to inertial forces is called the __________ number. Froude Euler Reynold Mach

Euler

Bernoulli's equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli's equation ? A. Fluid flow is frictionless & irrotational. B. Fluid flow is steady. C. Fluid flow is uniform & turbulent. D. Fluid is compressible. E. Fluid is incompressible. A, C, D B, D, E A, B, E A, D, E

A, B, E

Cavitation in a centrifugal pump results from high discharge pressure low barometric pressure high discharge velocity high discharge rate

low barometric pressure

For turbulent flow of newtonion fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is 0.5 1 0.66 < 0.5

For flow through a venturi at a particular discharge, the correct relationships among heads at points X, Y, and Z are h1 > h2 < h3 h1 > h2 > h3 h2 < h1 < h3 h1 < h2 < h3

h1 > h2 < h3

Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is 10√2π 5π/2 5√2π 5π/√2

5π/2

The time of oscillation of a floating body is longer, if metacentric height is increased. independent of the metacentric height. dependent on the buoyant forces only. none of these.

none of these.

What is the value of Fanning friction factor f ' for smooth pipe at NRe = 106 approximately ? 0.003 0.01 0.1 0.3

0.003

The hydraulic radius for flow in a rectangular duct of cross-sectional dimension H, W is √(HW/n) HW/[2(H+W)^2] HW/[4(H+W)^2] 2HW/(H+W)

HW/[2(H+W)^2]

In magnetic flow meters, voltage generation is due to the motion of conducting fluid through an externally generated uniform field. proportional to the fluid velocity. both (a) and (b). neither (a) nor (b).

both (a) and (b).

Air vessel provided in a reciprocating pump is for increasing the acceleration head. making the friction in pipe uniform. decreasing the acceleration head. none of these.

making the friction in pipe uniform.

A hydraulic accumulator comprises of a storage device and a control valve. a cylinder and a plunger. two pistons and two cylinders. a storage tank and a ram pump.

a cylinder and a plunger.

Bernoulli's equation for steady, frictionless, continuous flow states that the __________ at all sections is same. total pressure total energy velocity head none of these

total energy

A tube is specified by its thickness only outer diameter only thickness & outer diameter both inner diameter

thickness & outer diameter both

Uniform fluid flow occurs, when the derivative of the flow variables satisfy the following condition. ϑ/ϑt = 0 ϑ/ϑt = constant ϑ/ϑs = 0 ϑ/ϑs = constant

ϑ/ϑs = 0

Prandtl mixing length is applicable to laminar flow problems. a universal constant. zero at the pipe wall. none of these.

zero at the pipe wall.

The hydraulic diameter of an annulus of inner and outer radii Ri and Ro respectively is 4(Ro-Ri) √(Ro-Ri) 2(Ro-Ri) Ro + Ri

2(Ro-Ri)

Ratio of inertial forces to surface tension forces is called the __________ number. Euler Froude Mach Weber

Weber

In open channel flow in a rectangular channel, the ratio between the critical depth and the initial depth, when a hydraulic jump occurs is 0.5 0.84 1.84 1.25

1.84

The ratio of inertial forces to viscous forces is called the __________ number. Weber Mach Froude Reynold

Reynold

Enamels and paints are generally __________ fluid. reheopectic pseudo-plastic thixotropic dilatant

pseudo-plastic

With the increase in depth, the hydrostatic pressure in an unaccelerated incompressible fluid (in a constant gravitational field) decreases. increases linearly. increases exponentially. remains constant.

increases linearly.

Flow measurement in an open channel is done by a/an venturimeter orificemeter weir rotameter

weir

Newton's law of viscosity relates the shear stress and velocity. velocity gradient and pressure intensity. shear stress and rate of angular deformation in a fluid. pressure gradient and rate of angular deformation.

shear stress and rate of angular deformation in a fluid.

Applicability of Bernoulli's equation is limited to a/an __________ fluid, that does not exchange shaft work with the surroundings. incompressible non-viscous both (a) and (b) neither (a) nor (b)

both (a) and (b)

The equivalent diameter for fluid flow through square cross section channel of side 'x', for pressure drop calculation purpose is given by 4x 2x x √x

Hydraulic radius of 6" x 12" cross-section, is __________ inches. 2 0.5 1.5 none of these

Baffles in mixing tanks are provided to reduce swirling and vortex formation. increase the structural strength of the tank. aid in rotational flow. none of these

reduce swirling and vortex formation.

Which of the following equations is valid for laminar flow of a fluid through packed bed? Fanning equation Kozney - Karman equation Hagen-Poiseuille equation Blake-Plummer equation

Kozney - Karman equation

Forces acting on a particle settling in fluid are __________ forces. gravitational & buoyant. centrifugal & drag. gravitational or centrifugal buoyant drag. external, drag & viscous.

gravitational or centrifugal buoyant drag.

For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the square of the radial distance. radial distance linearly. inverse of the radial distance. elevation along vertical direction.

square of the radial distance.

In a dry packed bed, the pressure drop will be changed by increasing the flow rate as V^1.8 V^-0.8 V V^-1

V^1.8

Specific speed of a centrifugal pump depends upon the __________ head. suction delivery manometric none of these

none of these

Navier-Stokes equation is useful in the analysis of __________ fluid flow problems. non-viscous viscous turbulent rotational

viscous

The maximum discharge through a circular channel takes place, when the depth of the fluid flow is __________ times the pipe diameter. 0.25 0.5 0.66 0.95

0.95

When the head pumped against is less than the head of the fluid used for pumping, the usual device is a/an ejector blower injector airlift

airlift

Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will increase decrease remain unchanged data insufficient to predict relative pressure drop.

decrease

What is the value of co-efficient of discharge for square edged circular orifice (for β = 0.3 to 0.5) ? 0.61 - 0.63 0.5 - 0.75 0.75 - 0.90 0.35 - 0.55

0.61 - 0.63

A lubricant 100 times more viscous than water would have a viscosity (in Pa.s) 0.01 0.1 1 10

0.1

Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its inner diameter outer diameter thickness neither inner nor outer diameter

neither inner nor outer diameter

I.D. of 1/4" schedule 40 pipe is 0.364". I.D. of a 1/2" schedule 40 pipe would be __________ inch 4.728 0.5 0.622 0.474

0.622

Two liquids manometer is used for measuring small pressure differences in _____. liquids gases mixture of hydrocarbons none of these

gases

A piezometer provided in the pipe measures friction factor static pressure dynamic pressure none of these

static pressure

The pump used for irrigation purposes is generally designed for large capacity & high head. large capacity & low head. small capacity & high head. small capacity & low head.

large capacity & low head.

In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes less than atmospheric pressure. more than liquid vapor pressure. less than liquid vapor pressure. more than atmospheric pressure.

less than liquid vapor pressure.

Pressure gradient in the pipe flow is influenced by the diameter of pipe. velocity of the fluid. density & viscosity of the fluid. all (a), (b) and (c).

all (a), (b) and (c).

_________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2. Centrifugal Piston Plunger Vane

Plunger

Boiler feed water pump is usually a __________ pump. reciprocating gear multistage centrifugal diaphragm

multistage centrifugal

Viscosity of a liquid decreases __________ with rise in temperature. exponentially linearly logarithmically none of these

logarithmically

In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is the velocity of sound. dependent on its cross-sectional area. dependent on fluid viscosity. dependent on fluid density.

the velocity of sound.

Discharge in laminar flow through a pipe varies as the square of the radius. inversely as the pressure drop. inversely as the viscosity. as the square of the diameter.

as the square of the radius.

The lift of a ballon is increased, as it rises to a higher altitude. due to the weight of the atmospheric air, that it displaces. not dependent on the temperature of the atmosphere. none of these.

due to the weight of the atmospheric air, that it displaces.

In which of the following body shapes, the pressure drag is large compared to the friction drag ? Stream line body Two dimensional body Bluff body None of these

Bluff body

Major loss in sudden contraction in pipe flow is due to boundary friction. flow contraction. expansion of flow after sudden contraction. none of these.

flow contraction.

Which of the following can be used to create a flow of gas, where no significant compression is required ? Reciprocating compressor Blower Axial flow compressor Centrifugal compressor

Blower

The ratio of actual discharge to theoretical discharge through an orifice is equal to Cc . Cv Cc . Cd Cv . Cd Cd/Cv

Cc . Cv

A free jet of water of cross-sectional area 0.01m2 and a velocity of 20 m/s strikes a plate and then flows in a plane parallel to the plate as shown in the figure below. The horizontal component of the force on the support is 200 N 400 N 2000 N 4000 N

4000 N

Cp/Cv is termed as adiabatic constant Mach number Weber number Prandtl number

adiabatic constant

Which of the following is a Newtonian fluid? Rubber latex Sewage sludge Quicksand Non-colloidal solution

Non-colloidal solution

Which of the following valves will incur maximum pressure drop for the same discharge of water ? Globe valve Gate valve Needle valve Butterfly valve

Needle valve

Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor. less than more than same as none of these

more than

In deriving Bernoulli's equation, fluid is assumed to be incompressible, frictionless, steady, along a streamline. uniform, steady, incompressible, along a streamline. steady, density being pressure dependent, frictionless. none of these.

incompressible, frictionless, steady, along a streamline.

Unit of mass velocity is kg/hr kg/m2. hr kg/m2 kg/m3. hr

kg/m2. hr

With increase in molecular weight of the gas, the head developed by a centrifugal compressor will decrease increase remain same unpredictable

decrease

Pressure difference between two points in vessels, pipelines or in two different pipelines can be measured by a differential manometer. The pressure difference measured as the mm of water coloumn in case of mercury-water, differential manometer is equal to (where, H = difference in height of mercury column in mm). H 12.6 H 13.6 H 14.6 H

12.6 H

The boundary layer thickness at a given section along a flat plate __________ with increasing Reynold's number. increases decreases remains same may increase or decrease

decreases

Low specific speed of a pump implies that, it is a/an __________ pump. axial flow centrifugal mixed flow none of these

centrifugal

Pressure drop for laminar fluid flow through a circular pipe is given by 64/Re 32μLV/gc*D^2 4f*(L/D)*(v^2/2gc)*ρ f*(L/D)*(v^2/2gc)*ρ

32μLV/gc*D^2

For pumping slurry, one can use a __________ pump. reciprocating diaphargm centrifugal pneumatic

diaphargm

Bernoulli's equation describes the mechanical energy balance in potential flow. kinetic energy balance in laminar flow. mechanical energy balance in turbulent flow. mechanical energy balance in boundary layer.

mechanical energy balance in potential flow.

For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as d d^2 d^4 d_bar^2

d_bar^2

Which law/principle of solid mechanics is similar/equivalent to Newton's law of viscosity in fluid mechanics ? Archimedes principle. Newton's second law of motion. Hooke's law. Newton's third law of motion.

Hooke's law.

When larger particles e.g., grains are subjected to fluidisation, the corresponding bed produced is termed as the __________ bed. spouted sluggish boiling teeter

spouted

Minimum fluidisation velocity for a specific system depends upon the particle size. fluid viscosity. density of both the particle & the fluid. all (a), (b) and (c).

all (a), (b) and (c).

Potential flow is characterised by the irrotational and frictionless flow. irrotational and frictional flow. one in which dissipation of mechanical energy into heat occurs. formation of eddies within the stream.

irrotational and frictionless flow.

For the production of very high vacuum, a __________ pump is normally used. diffusion centrifugal jet ejector piston

diffusion

In parallel pipe problems, the head loss is the same through each pipe. discharge is the same through all the pipes. total head loss is equal to the sum of the head losses through each pipe. none of these.

head loss is the same through each pipe.

Fluid flow through a packed bed is represented by the __________ equation. Fanning's Ergun's Hagen-Poiseuille's none of these

Ergun's

_________ is an example of axial flow impeller. Paddle Turbine Propeller all (a), (b) and(c)

Propeller

Froude number is not a factor for Reynolds number greater than 300. when there is no vortex formation. for unbaffled tank. none of these.

when there is no vortex formation.

If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor). Q = Q1 + Q2 + Q3 V1 = V2 = V3 Q1 = Q2 = Q3 f = f1 + f2 + f3

Q = Q1 + Q2 + Q3

Horsepower requirement for given pump capacity depends upon the specific gravity of the liquid suction lift discharge head all (a), (b) and (c)

all (a), (b) and (c)

Bernoulli's equation accounts for the various momentums various masses different forms of mechanical energy none of these

different forms of mechanical energy

__________ pumps are a group of vacuum pumps. Hyter Sump Mono Submerged

Hyter

Plunger pumps are used for higher pressure slurries viscous mass none of these

higher pressure

What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate ? 0.5 1 1.5 2

0.5

In turbulent flow, the fluid particles move in an orderly manner. momentum transfer is on molecular scale only. shear stress is caused more effectively by cohesion than momentum transfer. shear stresses are generally larger than in a similar laminar flow.

shear stresses are generally larger than in a similar laminar flow.

Momentum correction factor used in fluid flow problems accounts for the change in direction of flow. change in total energy. change in pressure. non uniform direction of velocities at inlet & outlet sections.

non uniform direction of velocities at inlet & outlet sections.

Drag co-efficient for motion of spherical particles in a stationary fluid in the stoke's law range is 24/Nre 16/Nre 64/Nre 48/Nre

24/Nre

Design of the casing of centrifugal pump should be such as to minimise the back flow through impeller loss of kinetic head loss of static head none of these

loss of kinetic head

Which of the following is used for pumping crude oil from oil well ? Single stage centrifugal pump Gear pump Screw pump Duplex/triplex reciprocating pump

Duplex/triplex reciprocating pump

The energy loss in flow through ven-turimeter is less than that through flow nozzle, because in case of a flow nozzle, the length is shorter. throat diameter is more. sudden expansion of flow in the downstream occurs. distance between the throat and the inlet is more.

sudden expansion of flow in the downstream occurs.

_________ flow means the flow of incompressible fluid with no shear. Potential Streamline Creep Boundary layer

Potential

The continuity equation relates mass flow rate along a stream tube. relates work and energy. stipulates that Newton's second law of motion must be satisfied at every point in the fluid. none of these.

relates mass flow rate along a stream tube.

The energy loss over a length of pipeline according to Darcy-Weisbach equation for pipe flow is.....the mean velocity of flow. directly proportional to directly proportional to square of inversely proportional to inversely proportional to square of

directly proportional to square of

Pressure drop in a packed bed for laminar flow is given by the __________ equation. Kozney-Karman Blake-Plummer Leva's Fanning friction factor

Kozney-Karman

The fluid velocity varies as the cube of the cylinderical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid. Newtonion pseudoplastic dilatent Bingham plastic

pseudoplastic

Stoke's law is valid, when NRe, p is less than 2 100 2100 700

Froude number is the ratio of shear stress to gravitational stress. drag stress to shear stress. inertial stress to shear stress. inertial stress to gravitational stress.

inertial stress to gravitational stress.

Normal depth in open channel flow is the depth of flow in the channel corresponding to uniform flow. measured normal to the channel bed. corresponding to steady flow. none of these.

corresponding to uniform flow.

Which of the following flow measuring devices is an area meter ? Venturimeter Orifice meter Anemometer Rotameter

Rotameter

With decrease in particle size to be fluidised by a particular fluid, the operating range of fluidisation velocity widens squeezes does not change unpredictable from the data

does not change

Diaphragm valves are used for handling __________ fluids. corrosive viscous non-Newtonion solid suspended

corrosive

The schedule number of a pipe is an indication of its size roughness material density wall thickness

wall thickness

Minimum porosity for fluidisation is that corresponding to static bed. that corresponding to completely fluidised bed. the porosity of the bed when true fluidisation begins. less than that of the' static bed.

the porosity of the bed when true fluidisation begins.

A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now increase decrease remain same data insufficient to predict

decrease

Steady non-uniform flow is exemplified by flow through a/an long pipe at constant rate. long pipe at decreasing rate. expanding tube at increasing rate. expanding tube at constant rate.

expanding tube at constant rate.

The maximum depth from which a centrifugal pump can draw water is dependent on the speed of the pump. dependent on the power of the pump. 34 feet. 150 feet.

34 feet.

Hot wire anemometer is used to measure the velocity of liquids. temperature of liquids. velocity of gases. pressure of liquids.

velocity of gases.

Propeller type centrifugal pumps are most suitable for high capacity at high heads. high capacity at low heads. low capacity at high heads. low capacity at low heads.

high capacity at low heads.

The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid. Newtonion dilatant pseudoplastic non-Newtonion

Newtonion

Momentum transfer in laminar flow of fluids results due to the viscosity density velocity gradient none of these

velocity gradient

The capillary rise of mercury is maximum in glass tube of dia __________ mm. 0.5 1 2 5

0.5

Diaphragm pumps are used to transport solids liquids fluids slurries

slurries

For steady ideal fluid flow, the Bernoulli's equation states that the velocity is constant along a stream line. energy is constant throughout the fluid energy is constant along a stream line, but may vary across stream lines none of these

energy is constant along a stream line, but may vary across stream lines

In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller. speed of diameter of fluid velocity leaving all (a), (b) and (c)

all (a), (b) and (c)

A hydraulic press has a ram of 10 cms in diameter and a plunger of 1 cm in diameter. The force required on the plunger to raise a weight of 10 tons on the ram is __________ kg. 10 100 1000 10000

100

Choose the set of pressure intensities that are equivalent. 4.33 psi, 10 ft. of water, 8.83 inches of Hg. 4.33 psi, 10 ft. of water, 20.7 inches of Hg. 10 psi, 19.7 ft. of water, 23.3 inches of Hg. 10 psi, 19.7 ft. of water, 5.3 inches of Hg.

4.33 psi, 10 ft. of water, 8.83 inches of Hg.

Pick out the wrong statement about a streamline. It is always parallel to the main direction of the fluid flow. It is a line across which there is no flow and it is equivalent to a rigid boundary. Streamlines intersect at isolated point of zero velocity and infintie velocity. The fluid lying between any two streamlines can be considered to be in isolation and the streamline spacing varies inversely as the velocity.

It is always parallel to the main direction of the fluid flow.

The most serious disadvantage of an orificemeter is that it is not very accurate. it is very costly. most of the pressure drop is not recoverable. it is not suitable for measuring gas flow.

most of the pressure drop is not recoverable.

The discharge through a rectangular weir varies as H^1/2 H^5/2 H^2/5 H^3/2

H^3/2

In case of supersonic flow of a fluid through pipeline, the 'Mach number' is 0 1 < 1 > 1

> 1

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be __________ hp. 0.5 2 4 1

0.5

Transition length for turbulent flow in smooth pipe is equal to __________ times the pipe diameter. 0.5 5 50 100

Disc compensators are provided in large diameter fuel gas carrying pipelines to keep the pipe in proper orientation. make the pipe joint leak-proof. account for contraction/expansion of pipe due to temperature changes of the surroundings. account for the pressure variation side the pipeline.

account for contraction/expansion of pipe due to temperature changes of the surroundings.

Discharge from a 24 inch pipe of water at 10 ft/sec will be __________ ft3/sec. 7.65 32.36 48.22 125.6

125.6

Paper pulp is an example of __________ fluid. dilatant bingham plastic Newtonion pseudoplastic

bingham plastic

The ratio of the depth of flow to the diameter of the channel for maximum discharge in a circular channel in open channel flow is 0.1 0.55 0.95 1.85

0.95

A conical tank with a bottom opening of cross-sectional area A is filled with water and is mounted on supports as shown in the figure. What is the force F with which plate X must be pushed up to prevent water from leaking ? Assume that the density of air is negligible as compared to the density of water ρL. ρL . Vg ρL . A.Hg ρL . Vg/2 ρL .Vg/3

ρL . A.Hg

A relief valve provides back pressure for a cylinder. unloads a pump. is a directional control valve. none of these.

is a directional control valve.

An isentropic process is the one, in which pv = constant pv^r = constant pv^r = constant, and process is reversible none of these

pv^r = constant, and process is reversible

The distribution of shear stress in a stream of fluid in a circular tube is linear with radius for turbulent flow only. linear with radius for laminar flow only. linear with radius for both laminar & turbulent flow. parabolic with radius for both laminar & turbulent flow.

linear with radius for both laminar & turbulent flow.

For motion of spherical particles in a stationary fluid, the drag co-efficient in hindered settling compared to that in free settling is more less equal more or less, depending on the type of particle

Specific speed of a centrifugal pump relates it with another pump having the dynamic similarity same efficiency same speed geometrical similarity

dynamic similarity

Air vessel fitted to a reciprocating pump increases the work done. decreases the work done. causes cavitation. results in non-uniform discharge.

decreases the work done.

Deformation drag, which is caused by widespread deformation of fluid around the immersed body occurs when NRe is very small. is primarily a friction drag. is independent of body length. depends mainly on cross-sectional shape.

occurs when NRe is very small.

In isotropic turbulence, the __________ are equal to each other. temporal velocity components mean square of velocity fluctuations in the three co-ordinate directions root mean square of velocity fluctuations in the three co-ordinate directions none of these

mean square of velocity fluctuations in the three co-ordinate directions

Viscosity of water is about __________ times that of air at room temperature. 15 55 155 1050

Net positive suction head (NPSH) of a centrifugal pump must be greater than the vapour pressure of the liquid. less than the vapour pressure of the liquid. equal to the vapour pressure of the liquid. less than barometric pressure.

greater than the vapour pressure of the liquid.

Actual lift of a pump is always less than the theoretical lift and is limited by the specific gravity & temperature of the liquid. leakage & pressure decreasing at higher elevations. frictional resistance through pipes, fittings & passages. all (a), (b) and (c).

all (a), (b) and (c).

In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow? Discharge of water by a centrifugal pump being run at a constant rpm. Water flow in the suction and discharge pipe of a reciprocating pump. Water discharge from a vertical vessel in which constant level is maintained. Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe.

Water flow in the suction and discharge pipe of a reciprocating pump.

Nature of fluid flow during the opening of a valve in a pipeline is laminar unsteady steady uniform

unsteady

The __________ pressure is measured by a static tube. dynamic static total none of these

static

The speed of a sound wave in a gas is analogous to the speed of an elementary wave in an open channel. flow in an open channel. a disturbance travelling upstream in moving fluid. none of these.

an elementary wave in an open channel.

Mercury is an ideal barometric fluid mainly due to its high density. low compressibility. low capillary action. very low vapor pressure.

very low vapor pressure.

A spherical particle is falling slow in a viscous liquid such that Reynolds number is less than 1. Which statement is correct for this situation ? Inertial and drag forces are important. Drag, gravitational and buoyancy forces are impportant. Drag force and gravitational forces are important. None of the above.

Drag, gravitational and buoyancy forces are impportant.

A gas signifies absence of density. can resist shearing action. is incompressible. is a supercritical vapor.

is a supercritical vapor.

Pitot tube measures the __________ of a fluid. pressure average velocity average flow rate point velocity

point velocity

Which of the following is not dimension-less? Froude number Kinematic viscosity Pressure co-efficient None of these

Kinematic viscosity

In laminar flow through a round tube, the discharge varies linearly as the viscosity. inversely as the pressure drop. inversely as the viscosity. as the square of the radius.

inversely as the viscosity.

Which is not a variable head meter ? Venturimeter Pitot tube Rotameter None of these

Rotameter

The pipe wall thickness is minimum for a pipe of given nominal size having schedule number 160 120 80 40

Reynolds number for flow of water at room temperature through 2 cm dia pipe at an average velocity of 5 cm/sec is around 2000 10 100 1000

1000

Centrifugal pumps as compared to reciprocating pumps run at a lower speed for the same discharge. do not need priming. deliver fluid with pulsating/fluctuating discharge. can be run with discharge line valve closed for a short interval.

can be run with discharge line valve closed for a short interval.

What type of motion the fluid element undergoes, when it changes from one position to another position, such that the angle between the two sides change ? Rotation Translation Linear deformation Angular deformation

Angular deformation

In which type of fluid flow, the velocity of flow of fluid changes from point to point in the fluid at any instant ? Rotational Unsteady Turbulent Non-uniform

Non-uniform

The continuity equation in ideal fluid flow states that net rate of inflow into any small volume must be zero. energy is not constant along a streamline. energy is constant along a streamline. there exists a velocity potential.

net rate of inflow into any small volume must be zero.

Bernoulli's equation is not applicable, when the flow is irrotational. incompressible. viscous. all (a), (b) & (c).

all (a), (b) & (c).

The equivalent diameter for pressure drop calculation for a duct of square cross-section is given by(where, x = each side of the square duct) x √(πx) √(2x) √(x/2)

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid lies above the centroid of the plane surface. is independent of the specific weight of the fluid. is different for different fluids. is at the centroid of the plane surface

lies above the centroid of the plane surface.

Creeping flow around a sphere is defined, when particle Reynolds number is < 2100 < 0.1 > 2.5 < 500

< 0.1

Open channel liquid flow is most conveniently measured by a hot wire anemometer notch rotameter segmental orifice

notch

Toothpaste is a Bingham plastic pseudoplastic Newtonion liquid dilatent

dilatent

Slurries can be most conveniently pumped by a __________ pump. screw reciprocating gear centrifugal

centrifugal

Volute type of casing is provided in a centrifugal pump to convert velocity head to pressure head. convert pressure head to velocity head, reduce the discharge fluctuation. increase the discharge.

increase the discharge.

Each term of the Bernoulli's equation written in the form, P/ρ + g/gc.Z + v2/2gc, represents the total energy per unit _____. mass volume specific weight none of these

mass

In a free vortex, the velocity changes linearly with radial distance. flow is necessarily rotational. radial component of velocity is same everywhere. stream lines are not circular.

velocity changes linearly with radial distance.

Pick out the wrong statement. The eddy viscosity is a function of the type of turbulence involved. The eddy viscosity is a fluid property. The viscosity of gas increases with increase in temperature. The viscosity of a liquid increases with decrease in temperature.

The eddy viscosity is a fluid property.

The velocity distribution in direction normal to the direction of flow in plane Poiseuille flow is hyperbolic parabolic linear none of these

parabolic

In fluid flow, the stagnation point is defined as a point, where the __________ is zero. flow velocity pressure total energy all (a), (b) and (c)

flow velocity

A special type of liquid transporting device is the diffuser pump, in which __________ are minimised. bearing losses disk friction shock losses cavitation

shock losses

Which of the following is most prone to pulsating discharge flow ? Centrifugal pump Reciprocating pump Gear pump Axial flow pump

Gear pump

A streamline is the line connecting the mid-points of flow cross-sections. defined for uniform flow only. drawn normal to the velocity vector at every point. always the path of a particle.

drawn normal to the velocity vector at every point.

Which of the following relationship is valid for the equilibrium position of the float in a rotameter ?(where, Df= Drag force on the float Bf = Buoyant force on the float Wf = Weight of the float) Df + Bf = Wf Df = Bf + Wf Df + Bf + Wf =0 none of these

Df + Bf = Wf

Drag is defined as the force exerted by the fluid on the solid in a direction opposite to flow. fluid on the solid in the direction of flow. solid on the fluid. none of these.

fluid on the solid in the direction of flow.

The boundary layer is that part of a moving fluid, in which the fluid velocity is affected by the fluid flow pressure. constant. affected by the presence of a solid boundary. all (a), (b) and (c).

affected by the presence of a solid boundary.

The terminal velocity of a solid spherical particle falling through a stationary fluid mass in the Stoke's law range is proportional to the inverse of fluid viscosity. square of particle size. difference in the densities of the particle & fluid. all (a), (b) and (c).

all (a), (b) and (c).

Which of the following equations as suggested by Colebrook and White gives the increase in roughness of a new surface (ε0) with age/time (t) (where, ε = roughness of the surface after time't'. α = a co-efficient to be experimentally determined)? ε = ε0 + α.t ε = ε0 + α.t2 ε = ε0 + α.t3 ε = ε0 + α.t4

ε = ε0 + α.t

Nominal size of a pipe is an indication of its __________ diameter. inner outer approximate none of these

approximate

Fluidised beds are formed, when the fluid friction is zero gravity force is less than the fluid friction. pressure forces equal gravity forces. sum of the fluid friction and pressure forces is equal and opposite to gravity forces.

gravity force is less than the fluid friction.

A fluid is pumped at the rate of 10 lb/sec to a height of 55 ft. The horse power required is __________ hp. 1 10/55 5.5 1/55

Pick out the wrong statement: The vacuum pressure is always the negative gauge pressure. The pressure of the liquid measured by a piezometer tube is the gauge pressure. Manometric liquid should have high surface tension. The point at which the resultant pressure on an immersed surface acts, is known as the centre of gravity.

The point at which the resultant pressure on an immersed surface acts, is known as the centre of gravity.

Medium viscosity lubricating oil can be most ideally pumped by a __________ pump. vane piston centrifugal plunger

vane

In a fully turbulent flow (Re > 105) in a pipe of diameter 'd', for a constant pressure gradient, the dependence of volumetric flow rate of an incompressible fluid is d d^2 d^2.5 d^4

d^2.5

Pump used for the transportation of molten sodium in a fast breader reactor is a/an __________ pump. reciprocating plunger electromagnetic gear

electromagnetic

Small pressure differences in liquids is measured using a/an U-tube manometer. inclined tube manometer. pitot tube. none of these.

inclined tube manometer.

With increase in pump speed, its NPSH requirement decreases increases remains unaltered can either increase or decrease ; depends on other factors

increases

In the Newton's law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass is __________ the fluid viscosity. directly proportional to inversely proportional to inversely proportional to the square root of independent of

inversely proportional to

Gear pump is a positive displacement pump. is a centrifugal pump. is a non-positive displacement pump. can be started with delivery valve closed.

is a positive displacement pump.

Most of the centrifugal pumps used in chemical plants are usually __________ driven. steam diesel engine electric motor gas turbine

electric motor

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the back flow of fluid in the event of stoppage of pump. discharge pressure. flow of liquid during operation of the pump. all (a), (b) and (c).

back flow of fluid in the event of stoppage of pump.

Venturimeters, orificemeters and nozzles are used to measure the fluid discharge from a pipeline. The average fluid velocity in a pipeline can be measured by a/an weir hot wire anemometer cup and vane aneometer none of these

hot wire anemometer

The time taken for gravity flow of a fixed volume of liquid (as in Redwood viscometer) is directly proportional to its absolute viscosity. ratio of absolute viscosity to density. density. Reynolds number.

ratio of absolute viscosity to density.

The exit cone angle in case of a standard venturimeter is __________ the entrance cone angle. smaller than greater than equal to either (a) or (b)

smaller than

Sewage sludge is __________ type of non-Newtonion fluid. dilatant Bingham plastic Pseudo plastic none of these

Bingham plastic

Ratio of pressure and inertia force gives __________ number. Weber Mach Euler Froude

Euler

Permanent loss in a venturimeter is about __________ percent of the pressure drop in theupstream cone. 1 10 . 40 70

10 .

Volume of liquid displaced by a floating body is equivalent to its own weight submerged weight own volume submerged volume

own weight

The __________ is measured by a piezometric opening. dynamic pressure static pressure total pressure point velocity

total pressure

What is the pipe called which lifts water from a reservoir to a greater height than the initial level in the supply reservoir ? Penstock Siphon Tunnel Pressure pipeline

Siphon

Steady uniform flow is represented by flow through a/an long pipe at constant rate. long pipe at decreasing rate. expanding tube at constant rate. none of these.

long pipe at constant rate.

Pick out the correct statement pertaining to the flow through a converging-diverging tube. The value of Mach number is always unity at the throat. No shock wave develops in the tube when the Mach number at exit is greater than unity. Throughout the converging portion of the tube, the density increases in the downstream direction. none of these.

No shock wave develops in the tube when the Mach number at exit is greater than unity.

Cavitation can be prevented by suitably designing the pump. maintaining the suction head sufficiently greater than the vapour pressure. maintaining suction head = developed head. maintaining suction head lower than the vapour pressure.

maintaining the suction head sufficiently greater than the vapour pressure.

Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will increase decrease remain same be quadrupled

increase

Steady flow occurs, when the conditions change steadily with time. conditions are the same at the adjacent points at any instant. conditions do not change with time at any point. rate of the velocity change is constant.

conditions do not change with time at any point.

With increase in the ratio of orifice diameter to pipe diameter, the fraction of the orifice pressure differential that is permanently lost increases decreases remains unchanged increases exponentially

decreases

Which of the following two quantities when same, makes one pipe system equivalent to another pipe system ? Head & discharge Length & discharge Length & diameter Friction factor & diameter.

Head & discharge

The kinetic energy correction factor for velocity distribution of laminar flow is 0.5 1.66 1 2

1.66

Priming of a centrifugal pump is done to increase the mass flow rate of fluid. develop effective pressure rise by the pump. avoid chances of separation inside the impeller. none of these.

avoid chances of separation inside the impeller.

Bed pressure drop in an air fluidised bed of catalyst particles (ρp = 200 kg/m3, Dp = 0.05 cm) of 60 cm bed depth and bed porosity of 0.5 expressed in cm of water (manometer) is 90 60 45 30

For pipes that must be broken at intervals for maintenance, the connector used should be a/an union tee reducer elbow

union

A fluid is the one, which cannot remain at rest under the action of shear force. continuously expands till it fills any container. is incompressible. permanently resists distortion.

cannot remain at rest under the action of shear force.

One horsepower is equal to 550 lbf.ft/second 550 kgf.m/second both (a) and (b) 550 lbf.ft./hr

550 lbf.ft/second

A fluid (μ/ρ =0.01 cm2/s) is moving at critical flow condition (NRe = 2100) through a pipe of dia 3 cms. Velocity of flow is __________ cm/sec. 7 700 7000 630

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, σ = surface tension of mercury) d 1/d σ l/σ

The pressure drop per unit length of pipe incurred by a fluid 'X' flowing through pipe is Δp. If another fluid 'Y' having both the specific gravity & density just double of that of fluid 'X', flows through the same pipe at the same flow rate/average velocity, then the pressure drop in this case will be Δp 2Δp Δp2 Δp/2

2Δp

Fluid flow in a/an __________ is an example of pressure flow. partially filled pipeline pipe open channel river.

pipe

In the laminar boundary layer flow over a flat plate, the ratio (δ/x) varies as :(where, 'δ' is the boundary layer thickness and 'x' is the distance from the leading edge in the direction of flow). Re √Re 1/Re Re^-1/2

Re^-1/2

A rotameter through which air at room temperature and atmospheric pressure is flowing gives a certain reading for a flow rate of 100 cc/sec. If helium (molecular weight 4) is used and rotameter shows the same reading, the flow rate (cc/sec) is 26 42 269 325

269

A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is 4.4 KPa 2.94 KPa 3.7 KPa none of these

4.4 KPa

Select the wrong statement pertaining to flow of an incompressible fluid through a venturimeter. For frictionless flow, the fluid pressure entering the venturi meter will be exactly equal to that leaving the venturimeter. Discharge of fluid through a venturimeter depends upon the gage difference irrespective of the orientation of venturimeter. Venturimeter occupies less space than an orificemeter. Venturimeter incurs less power loss compared to an equivalent orificemeter.

Venturimeter occupies less space than an orificemeter.

Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will increase decrease remain same data insufficient to predict pressure drop

increase

The bulk modulus of elasticity of a liquid is zero for incompressible liquid. decreases with pressure. is independent of temperature & pressure. increases with pressure.

increases with pressure.

The inherent characteristic of an equal percentage valve relating flow rate 'q' with valve stem movement 'x' are described by the equation dq/dx = K dq/dx = Kq dq/dx = K/q dq/dx = Kq^2

dq/dx = K

Curve III in the above diagram represents a/an dilatent fluid pseudo plastic fluid ideal plastic none of these

pseudo plastic fluid

What is the ratio of total kinetic energy of fluid passing per second to the value obtained on the basis of average velocity (for laminar flow through a circular pipe)? 0.5 1 1.5 2

The line traced by a single fluid particle as it moves over a period of time is called __________ line. stream path equipotential none of these

path

The pressure head on sudden contraction in a horizontal pipe is converted into the __________ head. elevation velocity both (a) & (b) neither (a) nor (b)

velocity

A stream tube is that, which has __________ cross-section entirely bounded by stream lines. a circular any convenient a small a large

any convenient

The unit of velocity head is ft-lb/sec ft-lb/ft3 ft-lbf/lb ft-lbf/sec.

ft-lbf/lb

Which of the following properties of a fluid is responsible for offering resistance to shear ? Surface tension. Viscosity. Specific gravity. All (a), (b), and (c).

Viscosity

Erosion and pits formation on the impeller of a centrifugal pump may be due to cavitation. low speed of impeller. its operation with delivery valve closed for considerable time after starting the pump. off centering of pump with motor.

cavitation

The velocity profile exhibited by laminar flow of Newtonion fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an __________ with the apex at the centre line of the pipe. hyperbola parabola semi-circle semi-ellipse

parabola

A rotameter works on the principle of __________ pressure drop. constant variable both (a) & (b) neither (a) nor (b)

constant

The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids having high viscosities. moving at low velocities. both (a) & (b). neither (a) nor (b).

both (a) & (b).

The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the static submergence. net positive suction head (NPSH). cavitation sensitivity. priming.

net positive suction head (NPSH).

Piezometric head is the sum of the __________ heads. elevation & kinetic energy elevation & pressure kinetic energy & pressure none of these

elevation & pressure

Propellers are axial flow mixers. low speed impeller. used for mixingliquids of high viscosity. radial flow mixers.

axial flow mixers.

Which of the following is not an advantage of fluidisation from transfer operation point of view? Intimate contact of the fluid with all parts of the solid particles. Lower fluid pumping power requirement. Minimisation of temperature variation. Prevention of particle seggregation.

Lower fluid pumping power requirement.

Upto what value of 'Mach number', a fluid may be considered as incompressible ? 0.03 0.3 3 10

0.3

The head developed by a centrifugal pump is largely determined by the power of the pump. nature of the liquid being pumped. angle of the vanes and the speed of the tip of the impeller. vapour pressure of the liquid.

angle of the vanes and the speed of the tip of the impeller.

Pick out the wrong statement: Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer. Blowers develop a maximum pressure of 2 atmospheres. Friction losses in pipe fittings are generally expressed in terms of velocity heads. Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number.

Friction losses in pipe fittings are generally expressed in terms of velocity heads.

Flow rate of high velocity flue gas discharged through a stack to the atmosphere can be most conveniently measured by a _____. pitot tube manometer rotameter none of these

pitot tube

Potential flow is the flow of compressible fluids with shear. compressible fluids with no shear. incompressible fluids with shear. incompressible fluids with no shear.

incompressible fluids with no shear.

The value of critical Reynolds number for pipe flow is 1300 10,000 100,s000 none of these.

1300

Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate. elastic viscous gravity none of these

elastic

Fanning friction factor is equal to (where, fB = Blassius friction factor). fB/4 fB/2 4fB 2fB

fB/4

In case of coutte flow, the fluid flow is between two large flat parallel plates with _____. top plate moving and the bottom plate fixed. bottom plate moving and the top plate fixed. both the plates fixed. both the plates moving.

top plate moving and the bottom plate fixed.

In a stabilised soap bubble, pressure inside it compared to external pressure is more less same unpredictable

The component of acceleration resulting due to unsteady nature of flow is called __________ acceleration. normal local convective tangential

local

Power required for mixing Newtonion fluids is a function of the speed of impeller, diameter of impeller & viscosity. density & viscosity of fluid only. density of fluid, viscosity of fluid & impeller dia only. none of these.

none of these.

Multistage compressors are used in industry, because they reduce the cost of compressor. reduce the size requirement, resemble closely to isothermal compression. are easy to control.

resemble closely to isothermal compression.

The hydrodynamic and thermal boundary layers will merge, when Prandtl number is one. Schmidt number tends to infinity. Nusselt number tends to infinity. Archimedes number is greater than 10000.

Prandtl number is one.

Differential manometer measures the atmospheric pressure. sub-atmospheric pressure. pressure difference between two points. none of these.

pressure difference between two points.

For a stable equilibrium of a submerged body (where, G and B are centres of gravity & buoyancy respectively). G is above B B is above G B & coincide none of these

B is above G

With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss decreases increases remains constant increases linearly

remains constant

The vent valve provided in a liquid handling centrifugal pump is generally a needle valve. used to release any gases that might be vapour locking the pump. helpful in easy removal of samples. all (a), and (b) and (c).

all (a), and (b) and (c).

The discharge through a semi-circular weir varies as (where, H = Head of liquid.) H H2 H3/2 H1/2

The Mach number for hypersonic flow of compressible fluid is 1 > 1 > 4 < 2

> 4

Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.) √d d^2/3 d^4/5 d^1/3

d^4/5

Mass velocity in case of steady flow and through a constant cross-section conduit is independent of the temperature pressure both (a) & (b) neither (a) nor (b)

both (a) & (b)

The valve used for very remote and accurate control of fluid is a __________ valve. needle globe gate butterfly

needle

f = 16/NRe, is valid for turbulent flow laminar flow through an open channel steady flow none of these

none of these

A mixed flow centrifugal pump employs such an impeller, through which the flow is a combination of radial & axial flow. mixes the two fluids before pumping them. pumps the two fluids separately and then mixes them. employs impellers in both the radial & axial directions.

employs such an impeller, through which the flow is a combination of radial & axial flow.

In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature. lower than higher than equal to none of these

higher than

A rectangular surface 3' x 4', has the lower 3 edge horizontal and 6' below a free oil surface (sp. gr. 0.8). The surface inclination is 300 with the horizontal. The force on one side of the surface is(where, y = specific weight of water) 39.6y 48y 49.2y 58y

48y

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 x 103 VOM + 10.94 x 106 V2OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is 12 mm/s 16 mm/s 24 mm/s 28 mm/s

16 mm/s

One dimensional flow implies flow in a straight line. steady uniform flow. unsteady uniform flow. a flow which does not account for changes in transverse direction.

a flow which does not account for changes in transverse direction.

In case of turbulent flow of a Newtonion fluid in a straight pipe, the maximum velocity is equal to (where, Vavg = average fluid velocity) Vavg 1.2 Vavg 1.5 Vavg 1.8 Vavg

1.2 Vavg

Centrifugal compressors compared to reciprocating compressors require less space. have quieter operation. have lower operating costs. all (a), (b) and (c).

all (a), (b) and (c).

For laminar flow of Newtonion fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to(where, μ = fluid viscosity ) μ 1/μ √μ 1/√μ

1/μ

Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the drag on particles drag on coloumn walls bed height bed voidage

bed height

Slugging occurs in a fluidised bed, if the bed is narrow deep both (a) & (b) neither (a) nor (b)

both (a) & (b)

The continuity equation of fluid mechanics utilises the principle of conservation of ______. momentum mass energy both (b) & (c)

mass

Stoke's law is valid, when the particle Reynolds number is < 1 > 1 < 5 none of these

< 1

Which of the following is not a dimension-less parameter ? Pressure-co-efficient Froude number Kinematic viscosity Weber number

Kinematic viscosity

In which of the following cases, it is possible for flow to occur from low pressure to high pressure ? Flow of liquid upward in a vertical pipe. Flow through a converging section. Flow of air downward in a pipe. Impossible in a constant cross-section conduit.

Flow through a converging section.

The percentage slip in a reciprocating pump set is given by the % of (where, Q1 = actual discharge Q2 = theoretical discharge) Q1/Q2 Q2/Q1 (Q2-Q1)/Q1 (Q2-Q1)/Q2

(Q2-Q1)/Q2

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades. inlet tip of a blade curves in a direction opposite to that outlet tip of a blade curves in a direction opposite to that inlet tip of a blade is towards the direction outlet tip of a blade is towards the direction

outlet tip of a blade is towards the direction

For the same terminal conditions and fitting size, the least friction loss is incurred in a/an T-joint union 45° elbow 90°bend

union

A floating/submerged body is always stable, if its centre of gravity lies above its centre of buoyancy. and centre of buoyancy coincide. lies below its centre of buoyancy. lies above its meta centre.

lies below its centre of buoyancy.

Critical velocity in a pipe flow increases as fluid viscosity increases. increases as pipe diameter increases. independent of fluid density. none of these.

increases as pipe diameter increases.

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump develops a lower head. capacity is reduced. requires more power. all (a), (b) and (c).

all (a), (b) and (c).

In an incompressible flow of fluid, the fluid temperature remains constant. compressibility is greater than zero. density does not change with pressure & temperature. is frictionless.

density does not change with pressure & temperature.

The ratio of maximum to average velocity in case of streamline flow between parallel plates is 1 1.5 2 2.5

1.5

A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of __________ shape. circular rectangular triangular trapezoidal

circular

Pressure co-efficient is the ratio of pressure forces to __________ forces. gravity inertial viscous none of these

inertial

Which of the following conditions must be satisfied for lift force to be developed ? The body should be bluff body. The body should be stream lined. Circulation around the body is essentially required. The main stream velocity must approach the velocity of sound in that fluid medium.

Circulation around the body is essentially required.

The Reynolds number for an ideal fluid flow is 4 2100-4000 4000 ∞

∞

Fluid Mechanics Flashcards

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