Fluid Mechanics Flashcards by Karla Mae Mamangon

The fluid property, due to which, mercury does not wet the glass is

a. surface tension
b. viscosity
c. cohesion
d. adhesion

a. surface tension

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Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds

a. 4000
b. 2100
c. 1500
d. 3000

b. 2100

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When the momentum of one fluid is used for moving another fluid, such a device is called a/an

a. jet pump
b. blower
c. acid egg
d. none of these

a. 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

a. non-viscous.
b. incompressible.
c. both (a) and (b).
d. having no motion of one fluid layer relative to the other.

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

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Head developed by a centrifugal pump depends on its

a. speed
b. impeller diameter
c. both (a) and (b)
d. neither (a) nor (b)

c. 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

a. flow rate
b. mean velocity
c. both ‘a’ & ‘b’
d. neither ‘a’ nor ‘b’

b. mean velocity

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The head loss in turbulent flow in a pipe varies

a. as velocity
b. as (velocity)2
c. inversely as the square of diameter
d. inversely as the velocity

b. as (velocity)2

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Most commonly used joint in the underground pipe lines is the

a. sleevejoint
b. coupling
c. flange
d. expansion join

a. sleevejoint

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Schedule number of a pipe, which is a measure of its wall thickness, is given by

a. 1000 P’/S
b. 100 P’/S
c. 1000 S/P’
d. 10000 P’/S

a. 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

a. discharge.
b. suction.
c. suction minus vapor pressure of the liquid at suction temperature.
d. minus vapor pressure of the liquid at the discharge temperature.

c. 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

a. monotonically decreases.
b. decreases and then increases.
c. remains constant.
d. increases and then decreases.

a. monotonically decreases.

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The velocity profile for turbulent flow through a closed conduit is

a. logarithmic
b. parabolic
c. hyperbolic
d. linear

a. 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

a. relative roughness.
b. absolute roughness.
c. friction co-efficient for flows at equal Reynold number.
d. all (a), (b) & (c).

c. friction co-efficient for flows at equal Reynold number.

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Water hammer in a pipeline results from the

a. bursting of pipelines due to closure by a valve.
b. rapid pressure change due to a rapid change in the rate of flow.
c. pressure increase due to closure of a valve resulting in decrease in rate of flow.
d. none of these.

b. 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.

a. diaphragm
b. reciprocating
c. gear
d. centrifugal

d. centrifugal

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Which of the following denotes the effect of compressibility in fluid flow ?

a. Weber number
b. Mach number
c. Euler number
d. Reynolds number

b. Mach number

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Nominal size of the discharge pipe of a pump is usually __________ the nominal size of the inlet pipe.

a. smaller than
b. larger than
c. same as
d. twice

smaller than

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The terminal velocity of a small sphere settling in a viscous fluid varies as the

a. first power of its dimeter.
b. inverse of the fluid viscosity.
c. inverse square of the diameter.
d. square of the difference in specific weights of solid & fluid.

b. inverse of the fluid viscosity.

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If the discharge of a centrifugal pump is throttled, then its suction lift

a. increases
b. decreases
c. remains unchanged
d. data insufficient to predict

a. increases

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Foot valves provided in pumps are __________ valves.

a. relief
b. three/four way
c. pressure reducing
d. directional control

directional control

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At high Reynolds number

a. inertial forces control and viscous forces are unimportant.
b. viscous forces predominate.
c. inertial forces are unimportant and viscous forces control.
d. none of these.

a. inertial forces control and viscous forces are unimportant.

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Power loss in an orificemeter is __________ that in a venturimeter.

a. less than
b. same as
c. more than
d. data insufficient, cannot be predicted

c. more than

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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 ?

a. 0.5
b. 1
c. 1.5
d. 3

a. 0.5

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What is the normal range of exit cone angle of a venturimeter ?

a. 2 to 5
b. 7 to 15
c. 15 to 25
d. >25

b. 7 to 15

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The dimension of dynamic viscosity is a. ML-1T-1 b. L2T-1 c. LT-2 d. ML-1T-2

a. 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 a. same as that of A. b. one fourth as that of A. c. twice as that of A. d. four times as that of A.

b. one fourth as that of A.

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

d. (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. a. Bingham b. Newtonion c. perfect d. none of these

b. Newtonion

In fluid flow, cavitation is caused, if the a. fluid velocity decreases to zero. b. total energy decreases. c. both (a) and (b). d. flow pressure approaches its vapor pressure at the prevailing temperature.

d. flow pressure approaches its vapor pressure at the prevailing temperature.

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

d. 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). a. 24000 b. 24 c. 0.24 d. 0.44

d. 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) a. Vs/Dp2 b. Vs2/Dp2 c. Vs2/Dp3 d. Vs/Dp3

a. Vs/Dp2

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

d. 1000

Dimension of surface tension is(where, F = force, L = length) a. FL-1 b. F-1 . L c. F.L-2 d. F-2 . L

a. FL-1

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

d. None of these

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

b. more than

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

b. outside diameter

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

c. diaphragm

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

d. Weber number

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. a. 40 b. 34 c. 8 d. 37

c. 8

Pick out the wrong statement. a. Momentum transfer in laminar flow results from veclocity gradient. b. A fluid in equilibrium is not free from shear stress. c. The viscosity of a non-Newtonion fluid is a function of temperature only. d. both (b) and (c)

d. both (b) and (c)

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

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

Dimension of absolute viscosity is a. ML-1T-1 b. MLT-1 c. ML-1T d. MLT

a. ML-1T-1

__________ pumps are axial flow pumps. a. Turbine b. Propeller c. Diffuser d. none of these

b. Propeller

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

a. 2 to 3

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

b. 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 a. 10 KPa b. 20 KPa c. 30 KPa d. 40 KPa

b. 20 KPa

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

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

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

c. 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 a. copper b. tungsten c. chromium d. aluminium

b. tungsten

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

b. is constant along a stream line.

What causes cavitation in centrifugal pump ? a. High suction pressure b. Low barometric pressure c. Low suction pressure d. suction velocity

c. Low suction pressure

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

a. single stage vertical

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

c. 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 a. 0.5 b. 1 c. 2 d. 0.66

a. 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). a. FL-2T, ML-1T-1 b. FLT, ML-1T-1 c. ML-1T-3, F-1L2T d. F-1L2T-1, MLT-3

a. FL-2T, ML-1T-1

The line of action of the buoyant force passes through the centre of gravity of the a. submerged body. b. displaced volume of the fluid. c. of fluid vertically above the body. d. horizontal projection of the body.

b. displaced volume of the fluid.

Pick out the wrong statement. a. The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonion fluids is D/4L * delta p b. In the equation, T gc = k (du/dy)^n the value of 'n' for pseudoplastic and dilatant fluids are < 1 and >1 respectively. c. Shear stress for Newtonion fluid is proportional to the rate of shear in the direction perpendicular to motion. d. With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids.

d. 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 a. depends only on Reynolds number. b. does not depend on Reynolds number. c. depends on the roughness. d. none of these.

a. 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 a. moving b. static c. old d. hot

a. moving

What causes convective acceleration in fluid flow ? a. Steep slope in flow b. Unsteady nature of flow c. Non-uniformity of flow d. Turbulence in flow

c. Non-uniformity of flow

The Stoke's stream function applies to the a. irrotational flow only. b. ideal/non-viscous fluids only. c. cases of axial symmetry. d. of these.

c. cases of axial symmetry.

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

c. 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 a. 0.5 b. 1 c. 1.5 d. 2

d. 2

The simple pitot tube measures the __________ pressure. a. static b. dynamic c. total d. of these

c. total

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

a. amount of energy stored.

Three piping networks as shown in the figure are placed horizontally. They are made using identical pipe segments and are subjected to the same pressure drop across them. Assuming no pressure losses at junctions, the flow rates across the three networks are related as Q1 : Q2 : Q3. a. 1:√3: 2 b. 1:2:3 c. 1:2:2 d. 1:√2:√2

c. 1:2:2

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

c. 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. a. Re << 1, accelerating flow b. Re >> 1, accelerating flow c. Re << 1, decelerating flow d. Re >>1, decelerating flow

d. Re >>1, decelerating flow

Manometers measure the __________ pressure. a. vacuum as well as the atmospheric b. difference in c. absolute d. gage

b. difference in

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

d. Turbulent forces

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

a. Rotameter

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

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

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

d. none of these.

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

d. none of these.

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

a. energy which it can store.

(PBE Oct 2023) With increase in the temperature, viscosity of a liquid a. increases b. decreases c. remains constant d. may increase or decrease; depends on the liquid

b. decreases

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

b. 0.5 d

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

b. have different diameters.

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

c. are not subject to air binding.

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

d. surface tension

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

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

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

b. cross-section of the channel is reduced.

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

c. approximately as the square of the velocity.

For flow through an orifice from a reservoir, the actual velocity at the vena con-tracta is given by a. √2gh b. C.V. √2gh c. Cd √2gh d. Cc √2gh

b. C.V. √2gh

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 a. 0.3 b. 0.9 c. 0.03 d. 0.66

a. 0.3

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

b. -1

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

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

Venturimeter and orificemeter measures the __________ of the fluid. a. pressure b. maximum velocity c. average velocity d. point velocity

c. average velocity

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

b. 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. a. small differential b. atmospheric c. absolute d. gage

a. small differential

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

a. where there is no velocity gradient.

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

a. Reynolds number

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

b. force per unit mass equals acceleration.

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

d. momentum

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

c. intensity of pressure of the liquid.

Which of the following is the 'Blaussius equation', relating friction factor to the Reynolds number ? a. f = 0.079.NRe^-0.25 b. f^-0.5 = 4.07 loge (NRe√f)^-0.6 c. f^-0.5 = -4loge ( (ε/D / 3.70) + ((1.26 / NRe f^0.5)) d. none of these

a. f = 0.079.NRe^-0.25

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

d. all 'a', 'b' & 'c'

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

a. conservation of mass.

During ageing of fluid carrying pipes, the a. pipe becomes smoother with use. b. friction factor increases linearly with time. c. absolute roughness decreases with time. d. absolute roughness increases linearly with time.

d. absolute roughness increases linearly with time.

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

c. 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 a. unsteady through unchanged cross-section. b. steady through changing cross-section. c. steady and the cross-section is unchanged. d. unsteady and the cross-section is changed.

c. steady and the cross-section is unchanged.

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

d. inclined tube water.

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

c. 1/D5

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

a. increase

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

d. all compressible fluids.

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

b. (d1/d2)^0.5

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

c. remote recording of pressure difference.

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

c. tee

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

a. manometric

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

c. does not change the work requirement of the pump.

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

b. Mach

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

c. 2HB / (H+B)

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

d. non-steady non-uniform

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

b. 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 a. rotational and incompressible b. rotational and compressible c. irrotational and compressible d. irrotational and incompressible

b. rotational and compressible

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

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

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

b. density of the body.

Centrifugal pump is normally classified on the basis of the a. rpm. b. type of casing. c. impeller blade angle. d. number of blades in impeller.

b. type of casing.

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

c. At the wall

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

c. √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 a. Q/2 b. Q/4 c. Q/8 d. Q/16

d. 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 of vena-contracta / theoretical velocity ) a. Cd = Cc/Cv b. Cd = Cc.Cv c. Cd = Cv/cc d. none of these

b. Cd = Cc.Cv

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

c. not affected with moderate change in temperature & pressure.

Check valves are used a. at high pressure. b. in bends. c. for controlling water flow. d. for unidirectional flow.

d. for unidirectional flow.

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

a. varies parabolically across the section.

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

c. centrifugal

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

c. both (a) & (b).

Which of the fluid forces are not considered in the Reynold's equation of flow ? a. Viscous forces b. Turbulent forces c. Pressure forces d. Compressibility forces

d. Compressibility forces

For ideally incompressible fluid, the Mach number will be a. 1.5 b. 1 c. 0 d. 5

b. 1

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

c. positive acting rotary

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

a. 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. a. P, Q and R b. P and R c. R and S d. P, Rand S

a. P, Q and R

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

d. none of these

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

c. both (a) & (b)

Pick out the Hagen-Poiseulle's equation. a. Δp/ρ = 4f (L/D) (V^2 / 2gc) b. Δp = 32 μLV / gc.D^2 c. Δp/L = 150 (1-ε)/ε^3 ρVo^2 / g^2cDp d. Δp/L = 1.75 (1-ε)/ε^3 ρVo^2 / gcDp

b. Δp = 32 μLV / gc.D^2

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

a. 1/√M

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

c. adverse pressure gradient.

With increase in temperature, the vapor pressure of liquids a. increases b. increases linearly c. decreases d. remains constant

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. a. 17 b. 42 c. 84 d. 1.8

a. 17

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

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

c. 0.01

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

a. less power than

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

b. pitot tube

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

b. vaned diffusion casing.

Remote control valve is a __________ valve. a. gate b. butterfly c. needle d. globe

b. butterfly

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

c. Reynold number, relative roughness and head loss.

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

b. below

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

c. 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. a. size b. surface properties c. both (a) and (b) d. neither (a) nor (b)

c. both (a) and (b)

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

d. none of these

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

b. temperature is more or less uniform.

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

b. steady non uniform

Pick out the correct statement pertaining to transition/ entrance length in fluid flow. a. 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. b. Transition length for laminar flow of Newtonion fluids in a pipe of diameter 'd' is equal to 0.05. D.NRe. c. Transition length for turbulent flow of Newtonion fluids in a smooth pipe of diameter 'd' is equal to 50 D. d. all (a), (b) and (c).

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

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

c. 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. a. rotameter b. pitot tube c. venturimeter d. flow nozzle

b. pitot tube

During fluid flow, variation of shear stress(τ) with velocity gradientat (dv/dy) constant pressure temperature is shown below in the figure In the above figure, Binghom plastic is represented by the curve . a. V b. II c. III d. I

b. II

Speed of sound in an ideal gas depends on its a. temperature b. pressure c. specific volume d. none of these

a. temperature

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

a. less head & capacity

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

a. x

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

d. none of these.

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

a. Orifice meter

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

a. The fluid is incompressible.

In case of a pipe exit fitted with a nozzle, the a. conversion of kinetic head to pressure head is facilitated. b. conversion of pressure head to kinetic head is facilitated. c. 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. d. both (b) and (c)

d. both (b) and (c)

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

c. dilatant

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

c. Reciprocating pump

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

b. 50

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 a. 1 b. 0 c. < 1 d. > 1

c. < 1

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

c. 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) a. D = 1840 H^0.5/N b. D = 1840 N/H^0.5 c. H = 1840 D^0.5/N d. D = 1840 H/N

a. D = 1840 H^0.5/N

Which of the following pipe bends will incur the largest head loss ? a. U-bend b. 30° bend c. 45° bend d. 90° bend

a. U-bend

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

c. Rotameter

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

b. decreases due to reduced vapour pressure.

Pipes having diameter 14 inches or more are designated by their a. outside diameter b. inside diameter c. schedule number d. none of these

a. outside diameter

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

b. 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. a. 500 b. 200 c. 1000 d. 750

a. 500

The dimension of kinematic viscosity is a. ML-2T-1 b. L2T-1 c. ML-2T-2 d. none of these

b. 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 a. 20 m/sec b. 10 m/sec c. 5√2 m/sec d. 5 m/sec

b. 10 m/sec

Turbulent flow generally occurs for cases involving a. highly viscous fluid b. very narrow passages c. very slow motion d. none of these

d. none of these

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

b. 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. a. logarithmic b. parabolic c. hyperbolic d. linear

b. parabolic

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

d. useful for computing laminar flow problems.

N^2Re/NFr is called the __________ number. a. Brinkman b. Galileo c. Archimedes d. Euler

b. 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) a. 1 / y/3 b. 2y/3 c. 1/ y/4 d. 3y/4

b. 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 a. increases linearly with V. b. decreases linearly with V. c. decreases as V2. d. none of these.

a. increases linearly with V.

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

d. 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 a. pipe length b. fluid velocity in the pipe c. time taken to close the valve d. all (a), (b) and (c)

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

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

d. 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'? a. D Δp/8L b. D Δp/4L c. 8 . Vavg/D d. 4 . Vavg/D

c. 8 . Vavg/D

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

b. 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. a. 10 m b. 11 m c. 12 m d. 20 m

b. 11 m

The pressure head of a flow meter remains constant for a. venturimeter b. orificemeter c. rotameter d. pitot tube

c. rotameter

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

d. 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 a. head b. discharge c. efficiency d. none of these

b. discharge

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

d. Hot wire annemometer

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

c. both (a) & (b)

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

a. 0.44

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

a. 98

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

b. 200

Pick out the Kozney-Karman equation (valid for low NRe) for fluid flow through a packed bed of solids. a. Δp/ρ = 4f (L/D) (V^2 / 2gc) b. fp = 150(1-ε) / NRe + 1.75 c. - Δp gc D^2p ε^3 /L ˉvo μ (1-ε)^2 = 150 d. - Δp/δ L gc/v^2o Dp ε^3 / 1-ε = 1.75

c. - Δp gc D^2p ε^3 /L ˉvo μ (1-ε)^2 = 150

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 a. 0.5 b. 1 c. 2 d. 0.33

c. 2

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. a. logarithmic b. linear c. hyperbolic d. parabolic

a. logarithmic

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

a. centrifugal

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

a. 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. a. thermal conductivity b. electrical conductivity c. specific gravity d. electrical resistivity

b. electrical conductivity

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

a. I.D.

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

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

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

a. less than the average velocity through channels.

Cd is always __________ Cc. a. greater than b. less than c. equal to d. either more or less than

a. greater than

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

c. depends on the weight of the floating body.

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

b. High vapour pressure.

Characteristic curves for a centrifugal pump plotted against its capacity is shown in the diagram. x, y and z denote respectively a. efficiency, head and B.H.P. b. head, efficiency and B.H.P. c. B.H.P., efficiency and head d. efficiency, B.H.P. and head

b. head, efficiency and B.H.P.

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

a. manometric

The speed of sound in an ideal gas varies as the a. temperature b. pressure c. density d. none of these

d. none of these

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

c. 250-300

The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is a. < 1 b. 1 c. > 1 d. 2

a. < 1

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

a. 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 ? a. 0.5 b. 0.67 c. 1 d. 2

d. 2

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

b. back pressure

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

a. 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? a. Increasing the impeller speed and the volute area. b. Increasing the number of vanes in the impeller. c. Mounting of two or more impellers in series on a single shaft. d. Either of (a), (b) or (c).

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

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

a. normal

Specific speed for a centrifugal pump is a. N√ Q / H^(3/4) b. N√ Q / H^(2/3) c. N^3Q^5 / H^(1/3) d. N√ Q / H

a. N√ Q / H^(3/4)

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

a. parabola (vertex being at the opening).

Which of the following produces maximum pressure difference for transportation of gases ? a. Vaccum pumps b. Blowers c. Fans d. Compressors

d. Compressors

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

b. V2 > V1 and V2 > V3

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

d. 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. a. 33:3 b. 50 c. 66.6 d. 88.8

c. 66.6

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

d. flow in which transverse components are zero.

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

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

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

b. not constant along a streamline.

Hydraulic radius is the ratio of a. wetted perimeter to flow area. b. flow area to wetted perimeter. c. flow area to square of wetted perimeter. d. square root of flow area to wetted perimeter.

b. flow area to wetted perimeter.

The unit of bulk modulus of elasticity for a liquid in S.I. unit is a. N b. N/m c. N/m^2 d. N/m^3

c. N/m^2

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

c. as cube of

In the low Reynolds number region, the drag force on a sphere is proportional to a. V b. V^2 c. V^4 d. V^0.5

a. V

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

c. represents the conservation of mass.

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

b. Hagen and Poiseuille

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

a. butterfly valve

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

b. energy per unit weight

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

d. None of these

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

c. 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 a. increase. b. decrease. c. remain unchanged. d. increase or decrease depending on the pipe material.

a. 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. a. 4ng/3 b. 0.01ngH/4 c. 0.01ngH/8 d. 0.04ngH/3

a. 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 a. R b. R^2 c. R^4 d. R^0.5

c. R^4

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

a. 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. a. NPSH required. b. BHP required by the pump. c. head of the liquid pumped. d. all (a), (b) and (c).

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

Reynolds number is the ratio of a. viscous forces to gravity forces. b. inertial forces to viscous forces. c. viscous forces to inertial forces. d. inertial forces to gravity forces.

b. inertial forces to viscous forces.

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

a. (ρH - ρair)gH

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

a. pressure drop only.

N. second/m^2 is a. the S.I. unit of dynamic viscosity. b. the S.I. unit of kinematic viscosity. c. equivalent to one poise. d. equivalent to one stoke.

a. the S.I. unit of dynamic viscosity.

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

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

b. unidirectional

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).

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

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.

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

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

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

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.

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.

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.

Drag co-officient CD, in Stoke's law range is given by a. CD = 16 / Re,ρ b. CD = 24 / Re,ρ c. CD = 18.4 / Re,ρ d. CD = 0.079 / Re^0.25,ρ

b. CD = 24 / Re,ρ

In power law, ζ = A * [d/dy (u)] ^ 2 + B , then the fluid is a. Newtonian b. dilatant c. thixotropic d. rheopectic

a. Newtonian

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.

A Newtonion fluid is that a. which follows Newton's law of motion. b. which needs a minimum shear, before it starts deforming. c. for which shear & deformation are related as τ = μ ∂u / ∂y d. none of these.

c. for which shear & deformation are related as τ = μ ∂u / ∂y

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

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

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

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.

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.

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

b. dilatent

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

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

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

c. both (a) & (b).

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

a. √d

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

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.

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.

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. a. f1 = f2 b. f1 < f2 c. f1 > f2 d. data not sufficient to relate f1 & f2

c. f1 > f2

For an incompressible fluid, the bulk modulus of elasticity is a. 5 kg/m3 b. ∞ N/m2 c. 1 N 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 a. only when the fluid is frictionless. b. 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

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

b. pressure

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 theflow direction. c. the component being normal to the flow direction. d. none of these.

b. the component being parallel to theflow 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

Cocks are used to control a. water b. any liquid c. solids d. none of these

b. any liquid

The dimension of surface tension is a. ML^-2 b. MT^-2 c. MLT^-2 d. ML^-2T

b. MT^-2

Pick out the correct statement. a. Fanning friction factor is inversely proportional to Reynolds number always. b. 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. c. Mach number in an incompressible fluid is always unity. d. Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow.

d. 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 a. always inversely proportional to the Reynolds number. b. not dimensionless. c. not dependent on the roughness of the pipe. d. none of these.

d. none of these.

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

a. pseudoplastic

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

d. 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 a. evaporation b. cavitation c. sublimation d. stripping

b. cavitation

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

a. 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 a. 2xy / x+y b. xy / x+y c. x+y / 2xy d. x+y / xy

a. 2xy / x+y

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

a. torque applied

Cd for the orifice plate varies from a. 0.58 to 0.8 b. 0.93 to 0.98 c. 0.2 to 0.3 d. 0.02 to 0.03

a. 0.58 to 0.8

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

c. H^5/2

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

a. pitot tube

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

a. delivers unit discharge at unit head.

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

a. 2

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

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

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

c. is effective over wide range of viscosities.

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

c. form

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

b. ηm = ηv . ηma

When the pipe Reynold's number is 6000, the flow is generally a. viscous b. laminar c. turbulent d. transition

c. turbulent

Fanning equation is given by ΔP / ρ = 4f . L/D . v^2 / 2gc It is applicable to __________ region flow. a. transition b. laminar c. turbulent d. both (b) and (c)

d. both (b) and (c)

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

b. head varies as the square of speed.

For water, when the pressure increases, the viscosity a. also increases b. decreases c. remains constant d. first decreases, and then increases

d. first decreases, and then increases

The head loss due to sudden expansion is a. V1^2 - V2^2 / 2gc b. (V1-V2)^2 / 2gc c. V1-V2 / 2gc d. V1^1 - V2^2 / gc

b. (V1-V2)^2 / 2gc

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

a. type of orifice.

At low Reynolds number a. viscous forces are unimportant. b. viscous forces control. c. viscous forces control and inertial forces are unimportant. d. gravity forces control.

c. viscous forces control and inertial forces are unimportant.

For laminar flow through a closed conduit a. Vmax = 2Vav b. Vmax = Vav c. Vmax = 1.5Vav d. Vmax = 0.5Vav

a. 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. a. inverse b. square root c. second power d. first power

b. square root

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

b. long pipe at decreasing rate.

If Blausius or Darcey friction factor is 'f1' then the Fanning friction factor is equal to a. f1/4 b. 4f2 c. 2f1 d. f1/2

a. f1/4

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

a. 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 a. L ρv2/D b. L μ;V/D2 c. D ρv2/L d. μ V/L

a. L ρv2/D

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

b. 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 a. √x b. 1/√x c. x d. 1/x

a. √x

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

c. both (a) & (b)

Sewage sludge is an example of the __________ fluid. a. Bingham plastic b. Newtonion c. pseudoplastic d. dilatent

a. Bingham plastic

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

a. more than

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

a. 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 a. 1.3 b. 0.766 c. 0.87 d. none of these

b. 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 a. 25.61 kPa b. 11.77 kPa c. 14.86 kPa d. 21.13 kPa

b. 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 ? a. Decrease in effect b. Increase in thrust c. Develops noise d. Develops high pressure

d. Develops high pressure

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

b. directly as gas density.

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

a. Hagen-Poiseulle's equation

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

c. rotameter

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

b. less

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

b. 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 a. barometric pressure b. speed of the impeller c. diameter of the impeller d. both (b) and (c)

a. barometric pressure

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

c. 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 a. 8400 Pa/m b. 12600 Pa/m c. 18900 Pa/m d. 16800 Pa/m

b. 12600 Pa/m

One poise (unit of absolute/dynamic viscosity) is equivalent to one a. gm/cm^2. sec. b. gm/cm. sec. c. cm^2/sec. d. m^2/sec.

b. gm/cm. sec.

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

a. Nikuradse

Pressure drop for turbulent fluid flow through a circular pipe is given by a. 64/Re b. 32μLV / gc D^2 c. 4f . L/D . v^2/2gc . ρ d. f . L/D . ρ . v^2/2gc

c. 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 ? a. 0.64 b. 1.65 c. 0.32 d. 0.94

a. 0.64

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

b. M is below G

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

c. Rotameter

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

b. 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 a. 5 b. 14.1 c. 56.22 d. 28.2

d. 28.2

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

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

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

c. both (a) and (b).

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

b. turbine

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

b. 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 a. 0.42 b. 0.62 c. 0.82 d. 0.98

b. 0.62

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

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

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

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

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

a. protect the pump against developing excessive pressure.

Select the correct statement. a. The discharge through a venturimeter depends upon Δp only and is independent of orientation of the meter. b. 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. c. 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. d. 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.

a. 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 a. L/Dp / Re b. Re / Dp/L c. L/Dp / Re^2 d. Re^2 / Dp/L

a. L/Dp / Re

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

d. 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 a. more b. less c. equal d. either (a) or (b); depends on the viscosity of the fluid

a. more

Steady fluid flow occurs, when the derivative of flow variables satisfy the following condition. a. ∂ / ∂s = 0 b. ∂ / ∂t = 0 c. ∂ / ∂s = constant d. ∂ / ∂t = constant

b. ∂ / ∂t = 0

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

b. 10

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

c. 2

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

a. reduce discharge fluctuation.

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

a. velocity at a point in the flow.

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

b. Blake-Plummer

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

d. friction factor is independent of the relative roughness.

Which of the following has the minimum compressibility ? a. Water at room temperature b. Air at room temperature c. Oxygen at room temperature d. Nitrogen at room temperature

a. Water at room temperature

In case of centrifugal fan or blower, the gas capacity varies as a. speed b. (speed)^2 c. (speed)^3 d. (speed)^0.5

a. speed

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

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

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

a. 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 a. parabolic b. flat c. flat near the wall and parabolic in the middle d. parabolic near the wall and flat in the middle.

d. parabolic near the wall and flat in the middle.

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

c. both (a) & (b).

Mach number is the ratio of the speed of the a. fluid to that of the light. b. light to that of the fluid. c. fluid to that of the sound. d. sound to that of the fluid.

c. fluid to that of the sound.

A piezometer opening measures the __________ fluid pressure. a. static b. undisturbed c. total d. dynamic

b. undisturbed

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

d. constant

The unit of dynamic viscosity in SI unit is a. kg/m . sec b. N/m^2 c. m^2 /sec. d. m/N. sec.

a. kg/m . sec

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

d. V^2

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

b. fluid flow through helical pipes.

The equation given below is called the __________ . f^-0.5 = 4.07 loge (NRe√f)^-0.6 a. Colebrook formula b. Von-Karman equation c. Fanning equation d. none of these

b. Von-Karman equation

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

b. 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. a. dilatant b. pseudoplastic c. Bingham plastic d. Newtonion

a. dilatant

Kinetic energy of fluid per unit weight represented by the velocity head is given by a. 2v^2/gc b. v^2/2gc c. ρv^2/gc d. ρ.v^2/2gc

b. v^2/2gc

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

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

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

a. viscous

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

a. minimum liquid cross-section.

Pick out the Blake-Plummer equation (valid for large NRe) for fluid flow through beds of solids. a. Δp/ρ = 4f . L/D . v^2/2gc b. fp = 150(1-ε)/NRe + 1.75 c. Δp . gc . D^2p. ε^3 / L . ˉvo . μ(1-ε)^2 = 150 d. Δp/δ . L . gc/v^2o . Dp ε^3 / 1-ε = 1.75

d. Δp/δ . L . gc/v^2o . Dp ε^3 / 1-ε = 1.75

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) a. 1/μ b. μ c. μ^2 d. 1/μ^2

b. μ

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

a. increase

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

a. solids are completely entrained.

Glass pipes can be joined by a. flanges b. welding c. soldering d. bell and spigot joint

d. 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 a. same in both the tubes. b. greater in 1 mm dia tube. c. greater in 0.5 mm dia tube. d. zero in both the tubes.

c. 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 a. 2 b. <2 c. >2 d. 1/2

a. 2

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

a. surface tension

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

b. is the evolute o

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 ? a. 40° and 140° b. 45° and 60° c. 90° and 80° d. 20° and 120°

a. 40° and 140°

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

a. use of floats of different densities.

Which of the following is dimensionless ? a. Angular velocity b. Fanning friction factor c. Specific volume d. None of these

b. 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. a. 600 b. 660 c. 1.1 d. 60

b. 660

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

c. 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 10^3 VOM + 10.94 x 10^6 V^2OM (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 ? a. 0.2 b. 0.5 c. 0.7 d. 0.8

c. 0.7

Dimension of kinematic viscosity is MLT^-1 L^2 . T^-1 L^2T L^2 . T^-2

L^2 . T^-1

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

c. 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 a. open b. closed c. either open or closed d. none of these

b. closed

__________ forces do not act in case of fluid flow. a. Elastic b. Tensile c. Vibratory d. Centrifugal

b. Tensile

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

b. Newtonion

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

c. adverse pressure gradient.

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. a. piston b. gear c. positive displacement d. sump

b. gear

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

b. colour

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 a. Δp b. < Δp c. > Δp d. Δp2

c. > Δp

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

b. A Newtonion fluid obeys Newton's law of cooling.

What is the unit of kinematic viscosity in SI unit ? a. M^2/sec b. N/m^2 . sec c. Kg . sec/m d. None of these

a. M^2/sec

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

a. press

The contraction co-efficient for Borda's mouthpiece (for frictionless fluid) is a. 0.1 b. 0.5 c. 0.94 d. 1

b. 0.5

Potential function is applicable only for __________ flow. a. irrotational b. turbulent c. steady d. none of these

a. irrotational

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

c. lift water from a well by using compressed air.

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

a. fluid flow rate & friction loss

Pick out the correct statement pertaining to venturimeter. a. A venturimeter with a fixed pressure drop discharges more, when the flow is vertically downward, than when the flow is vertically upward. b. The co-efficient of contraction of a venturimeter is always unity. c. 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. d. none of these.

d. none of these.

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

c. rotary

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

c. both (a) and (b)

What is the speed of sound (m/sec) in ordinary water ? a. 1500 b. 330 c. 1000 d. 3000

a. 1500

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

a. Fluid flow at the inlet to a nozzle

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

a. kinetic head gets converted into static head.

The head loss due to sudden contraction is proportional to a. velocity b. velocity head c. turbulence d. none of these

b. velocity head

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

a. 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 ? a. Sewage sludge b. Rubber latex c. Blood d. Sugar solution

a. Sewage sludge

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

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

Which law is followed by the velocity distribution in the turbulent boundary layer? a. Parabolic law b. Linear law c. Logarithmic law d. None of these

c. Logarithmic law

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

b. first power of the roughness.

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

c. both (a) & (b)

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

b. Venturimeter

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

a. V/Vmax = (x/r)^1/7

Which of the following has the maximum compression ratio ? a. Blower b. Compressor c. Vacuum pump d. Fan

c. Vacuum pump

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

d. all geometrical, dynamic and kinematic similarity.

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

a. Cv . √2gH

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

a. V^2

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

c. expanding tube at increasing rate.

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

a. 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. a. 2 b. 4 c. 8 d. 5.5

a. 2

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

c. near each other,

section 10 cot'd

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Fluid Mechanics Flashcards

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