Section 13 Flashcards by justin balladares

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

a. 0.1
b. 0.55
c. 0.95
d. 1.85

c. 0.95

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A relief valve

a. provides back pressure for a cylinder.
b. unloads a pump.
c. is a directional control valve.
d. none of these.

c. is a directional control valve.

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An isentropic process is the one, in which

a. pv = constant
b. pvr = constant
c. pvr = constant, and process is reversible
d. none of these

c. pvr = constant, and process is reversible

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The distribution of shear stress in a stream of fluid in a circular tube is

a. linear with radius for turbulent flow only.
b. linear with radius for laminar flow only.
c. linear with radius for both laminar & turbulent flow.
d. parabolic with radius for both laminar & turbulent flow.

c. linear with radius for both laminar & turbulent flow.

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For motion of spherical particles in a stationary fluid, the drag co-efficient in hindered settling compared to that in free settling is

a. more
b. less
c. equal
d. more or less, depending on the type of particl

a. more

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Specific speed of a centrifugal pump relates it with another pump having the

a. dynamic similarity
b. same efficiency
c. same speed
d. geometrical similarity

a. dynamic similarity

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Air vessel fitted to a reciprocating pump

a. increases the work done.
b. decreases the work done.
c. causes cavitation.
d. results in non-uniform discharge.

b. decreases the work done.

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Deformation drag, which is caused by widespread deformation of fluid around the immersed body

a. occurs when NRe is very small.
b. is primarily a friction drag.
c. is independent of body length.
d. depends mainly on cross-sectional shape.

a. occurs when NRe is very small.

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In isotropic turbulence, the __________ are equal to each other.

a. temporal velocity components
b. mean square of velocity fluctuations in the three co-ordinate directions
c. root mean square of velocity fluctuations in the three co-ordinate directions
d. none of these

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

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Viscosity of water is about __________ times that of air at room temperature.

a. 15
b. 55
c. 155
d. 1050

b. 55

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Net positive suction head (NPSH) of a centrifugal pump must be

a. greater than the vapour pressure of the liquid.
b. Less than the vapour pressure of the liquid.
c. equal to the vapour pressure of the liquid.
d. less than barometric pressure.

a. greater than the vapour pressure of the liquid.

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Actual lift of a pump is always less than the theoretical lift and is limited by
the

a. specific gravity & temperature of the liquid.
b. leakage & pressure decreasing at higher elevations.
c. frictional resistance through pipes, fittings & passages.
d. all (a), (b) and (c)

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

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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?

a. Discharge of water by a centrifugal pump being run at a constant rpm.
b. Water flow in the suction and discharge pipe of a reciprocating pump.
c. Water discharge from a vertical vessel in which constant level is maintained.
d. Low velocity flow of a highly viscous liquid through a
hydraulically smooth pipe.

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

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Nature of fluid flow during the opening of a valve in a pipeline is

a. laminar
b. unsteady
c. steady
d. uniform

b. unsteady

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The __________ pressure is measured by a static tube.

a. dynamic
b. static
c. total
d. none of these

b. static

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The speed of a sound wave in a gas is analogous to the speed of

a. an elementary wave in an open channel.
b. flow in an open channel.
c. a disturbance travelling upstream in moving fluid.
d. none of these.

a. an elementary wave in an open channel.

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Mercury is an ideal barometric fluid mainly due to its

a. high density.
b. low compressibility.
c. low capillary action.
d. very low vapor pressure.

d. very low vapor pressure.

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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 ?

a. Inertial and drag forces are important.
b. Drag, gravitational and buoyancy forces are important.
c. Drag force and gravitational forces are important.
d. None of the above.

b. Drag, gravitational and buoyancy forces are important.

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A gas

a. signifies absence of density.
b. can resist shearing action.
c. is incompressible.
d. is a supercritical vapor.

d. is a supercritical vapor.

Pitot tube measures the __________ of a fluid.

a. pressure
b. average velocity
c. average flow rate
d. point velocity

d. point velocity

Which of the following is not dimension-less?

a. Froude number
b. Kinematic viscosity
c. Pressure co-efficient
d. None of these

b. Kinematic viscosity

In laminar flow through a round tube, the discharge varies

a. linearly as the viscosity.
b. inversely as the pressure drop.
c. inversely as the viscosity.
d. as the square of the radius.

c. inversely as the viscosity.

Which is not a variable head meter ?

a. Venturimeter
b. Pitot tube
c. Rotameter
d. None of these

c. Rotameter

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

d. 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 a. 2000 b. 10 c. 100 d. 1000

d. 1000

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

d. 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 ? a. Rotation b. Translation c. Linear deformation d. Angular deformation

d. 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 ? a. Rotational b. Unsteady c. Turbulent d. Non-uniform

d. Non-uniform

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

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

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

d. 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) a. x b. √𝜋𝑥 c. √2x d. √𝑥/2

a. x

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

b. is independent of the specific weight of the fluid.

Drag co-efficient for flow past immersed body is the ratio of __________ to the product of velocity head and density. a. shear stress b. shear force c. average drag per unit projected area d. none of these

c. average drag per unit projected area

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

b. < 0.1

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

b. notch

Toothpaste is a a. Bingham plastic b. pseudoplastic c. Newtonion liquid d. dilatent

d. dilatent

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

d. centrifugal

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

d. increase the discharge.

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

a. velocity changes linearly with radial distance.

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

b. The eddy viscosity is a fluid property.

The velocity distribution in direction normal to the direction of flow in plane Poiseuille flow is a. hyperbolic b. parabolic c. linear d. none of these

b. parabolic

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

a. flow velocity

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

c. shock losses

Which of the following is most prone to pulsating discharge flow ? a. Centrifugal pump b. Reciprocating pump c. Gear pump d. Axial flow pump

c. Gear pump

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

c. 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) a. Df + Bf = Wf b. Df = Bf + Wf c. Df + Bf + Wf =0 d. none of these

a. Df + Bf = Wf

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

b. 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 a. Affected by the fluid flow pressure. b. constant. c. affected by the presence of a solid boundary. d. all (a), (b) and (c).

c. affected by the presence of a solid boundary.