Section 6 Flashcards by justin balladares

The distance between metacentre and __________ is called metacentric height.

A. water surface
B. centre of gravity
C. centre of buoyancy
D. none of these

B. centre of gravity

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Check valve is used for __________ flow.

A. very precise control of
B. unidirectional
C. multidirectional
D. none of these

B. unidirectional

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Capacity of a rotary gear pump can be varied by

A. changing the speed of rotation.
B. bleeding air into suction.
C. bypassing liquid from the suction or discharge line.
D. all (a), (6) and (c).

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

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For a given Reynolds number, in a hydraulically smooth pipe, further smoothening __________ the friction factor.

A. brings about no further reduction of
B. increases
C. decreases
D. none of these

A. brings about no further reduction of

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Power number is the ratio of

A. drag stress to inertial stress.
B. inertial stress to drag stress.
C. inertial stress to gravitational stress.
D. gravitational stress to drag stress.

A. drag stress to inertial stress.

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For the same flow rate of a fluid, the pressure drop is the least for

A. venturimeter
B. orificemeter
C. flow-nozzle
D. Δp is same for all

A. venturimeter

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The momentum correction factor for the velocity distribution of laminar flow is

A. 1.3
B. 1.66
C. 2.5
D. none of these

D. none of these

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The valve commonly used in pipes larger than 2” dia is a

A. globe valve
B. plug-cock
C. gate valve
D. check valve

C. gate valve

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Foot valves are provided in the suction line of a centrifugal pump to

A. avoid priming, every time we start the pump.
B. remove the contaminant present in the liquid.
C. minimise the fluctuation in discharge.
D. control the liquid discharge.

A. avoid priming, every time we start the pump.

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An ideal fluid is

A. frictionless & incompressible.
B. one, which obeys Newton’s law of viscosity.
C. highly viscous.
D. none of these.

A. frictionless & incompressible.

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In area meter (e.g., rotameter), with increase in the fluid flow rate, the

A. pressure drop increases linearly.
B. pressure drop is almost constant.
C. area through which fluid flows does not vary.
D. none of these.

B. pressure drop is almost constant.

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The buoyant force acting on a floating body is dependent on the

A. viscosity of the liquid.
B. weight of the liquid displaced.
C. depth of immersion of the body.
D. surface tension of the liquid.

B. weight of the liquid displaced.

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

A. same rate of flow passes through

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Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?

A. Fanning equation
B. Blake-Pllummer equation
C. Hagen-Poiseulle equation
D. Kozney-Karman equation

B. Blake-Pllummer equation

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The flow of gas along a pipe in the direction of decreasing pressure causes decrease in its

A. viscosity
B. specific volume
C. velocity
D. none of these

B. specific volume

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Centrifugal pump can’t be used to pump

A. molten sodium (used as a coolant in Fast Breeder Reactor).
B. moderately viscous vegetable oil used in soap industry.
C. thick molten soap at 80°C.
D. none of the above.

C. thick molten soap at 80°C.

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A stream line is

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

A. fixed in space in steady flow.

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

A. <4
B. >4
C. > 12.5
D. <10

C. > 12.5

Quicksand is an example of a __________ fluid.

A. bingham plastic
B. dilatent
C. Newtonion
D. Pseudoplastic

B. dilatent

The line of action of the buoyant force acts through the

A. centroid of the displaced volume of fluid.
B. centre of gravity of a submerged body.
C. centroid of the volume of any floating body.
D. none of these.

A. centroid of the displaced volume of fluid.

Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.)
A. square root of d
B. d^1/3
C. d^2
D. d^2/3

A. square root of d

Differential manometer measures the

A. absolute pressure
B. gauge pressure
C. pressure difference
D. pressure gradient

C. pressure difference

The pressure and power requirement of a gas fan at constant speed & capacity varies __________ the gas density.

A. directly as
B. inversely as square root of
C. inversely as
D. as square of

A. directly as

Gradually varied flow in open channel is a/an __________ flow.

A. steady uniform
B. steady non-uniform
C. unsteady uniform
D. unsteady non-uniform

B. steady non-uniform

Cavitation in a centrifugal pump can be avoided by keeping the A. inlet pressure high B. outlet pressure low C. inlet pressure low D. outlet pressure high

A. inlet pressure high

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

C. 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. A. 1.8 B. 12.4 C. 186.2 D. 736.4

B. 12.4

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

D. 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. A. equivalent B. transition C. Prandtl mixing D. none of these

B. transition

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

C. 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. A. two B. three C. four D. eight

C. four

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

A. a constant velocity with no acceleration.

For an incompressible fluid, the bulk modulus of elasticity is A. 5 kg/m^3 B. ∞ N/m^2 C. 1N D. 0 N/m

B. ∞ N/m2

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

D. 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 B. only when the fluid is frictionless. A. only when the fluid is at rest having zero velocity. C. when there is no motion of one fluid layer relative to an adjacent layer. D. regardless of the motion of one fluid layer relative to an adjacent layer.

C. 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. A. I, II, III B. II, III, V C. I,II,V D. II, IV, V

B. 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 ? A. < 0.3 B. >3 C. 50 D. 1

A. < 0.3

Boundary layer exists in flow A. of real fluids. B. over flat surfaces only. C. in pipes only. D. of ideal fluids only.

A. of real fluids.

Rubber latex is an example of __________ fluid. A. dilatent B. Newtonion C. pseudoplastic D. Bingham plastic

C. pseudoplastic

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

A. area of surface in contact.

A venturimeter measures the A. velocity head B. pressure C. point velocity D. none of these

D. none of these

Gradually varying fluid flow is an example of __________ flow. A. non-steady uniform B. non-steady non-uniform C. steady uniform D. steady non-uniform

A. non-steady uniform

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

B. the component being parallel to the flow direction.

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

A. reciprocating