Fluid Mechanics

Question 1

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

Answer 1

surface tension

Question 2

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

Answer 2

2100

Question 3

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

Answer 3

jet pump

Question 4

The head loss in turbulent flow in a pipe varies

Answer 4

as (velocity)^2

Question 5

Most commonly used joint in the underground pipe lines is the

Answer 5

sleevejoint

Question 6

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

Answer 6

1000 P’/S

Question 7

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

Answer 7

suction minus vapor pressure of the liquid at suction temperature.

Question 8

With increasing flow rate, the hydraulic efficiency of a centrifugal pump

Answer 8

monotonically decreases.

Question 9

The velocity profile for turbulent flow through a closed conduit is

Answer 9

logarithmic

Question 10

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

Answer 10

friction co-efficient for flows at equal Reynold number.

Question 11

Water hammer in a pipeline results from the

Answer 11

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

Question 12

Molten soap mass is transported by a __________ pump.

Answer 12

centrifugal

Question 13

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

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

Answer 13

Mach number

Question 14

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

Answer 14

smaller than

Question 15

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

Answer 15

inverse of the fluid viscosity.

Question 16

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

Answer 16

increases

Question 17

Foot valves provided in pumps are __________ valves.

Answer 17

directional control

Question 18

At high Reynolds number

Answer 18

inertial forces control and viscous forces are unimportant.

Question 19

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

Answer 19

more than

Question 20

The terminal velocity of a particle moving through a fluid varies as dpn. What is the value of n’ for Newton’s law regime ?

Answer 20

0.5

Question 21

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

Answer 21

7 to 15

Question 22

The dimension of dynamic viscosity is

Answer 22

ML^-1T^-1

Question 23

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

Answer 23

one fourth as that of A.

Question 24

The pitot static tube does not measure the __________ pressure.

a. static
b. total
c. difference in static & dynamic
d. all (a), (b) and (c)

Answer 24

all of these

Question 25

The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a __________ fluid.

Answer 25

Newtonion

Question 26

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

Answer 26

2

Question 27

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^-6m^2/s).

Answer 27

0.44

Question 28

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)

Answer 28

Vs/Dp^2

Question 29

The maximum delivery pressure of compressors can be upto __________ atmospheres.

Answer 29

1000

Question 30

Dimension of surface tension is(where, F = force, L = length)

Answer 30

FL^-1

Question 31

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

Answer 31

None of these

Question 32

Co-efficient of velocity is __________ the coefficient of discharge.

Answer 32

more than

Question 33

All pipes of a particular nominal size have the same

Answer 33

outside diameter

Question 34

For the transfer of solution of thick slurry, the pump used is a __________ pump.

Answer 34

diaphragm

Question 35

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

Answer 35

Weber number

Question 36

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.

Answer 36

8

Question 37

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)

Answer 37

all of these

Question 38

Dimension of absolute viscosity is

Answer 38

ML^-1T^-1

Question 39

__________ pumps are axial flow pumps.

Answer 39

Propeller

Question 40

Brownian movement is prominent in the particle size range of __________ microns in case of settling of a particle in a fluid.

Answer 40

2 to 3

Question 41

For a particle settling in water at its terminal settling velocity, which of the following is true ?

Answer 41

Weight = buoyancy + drag

Question 42

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

Answer 42

20 KPa

Question 43

Pick out the correct statement.
a. A forced vortex occurs when fluid rotates as a solid about an axis.
b. 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.

Answer 43

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

Question 44

Shear stress in a fluid flowing in a round pipe

Answer 44

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

Question 45

The resistance wire used in a hot wire anemometer for conducting electrical current is made of

Answer 45

tungsten

Question 46

Two dimensional stream function

Answer 46

is constant along a stream line.

Question 47

What causes cavitation in centrifugal pump ?

Answer 47

Low suction pressure

Question 48

Draining of shallow pits or sump is done by a sump pump, which is a __________ pump.

Answer 48

single stage vertical

Question 49

A hydraulic ram acts as a/an __________ pump.

Answer 49

impulse

Question 50

The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonion fluid in a circular pipe is

Answer 50

0.5

Question 51

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

Answer 51

FL^-2T, ML^-1T^-1

Question 52

The line of action of the buoyant force passes through the centre of gravity of the

Answer 52

displaced volume of the fluid.

Question 53

The normal stress is the same in all directions at a point in a fluid, when the fluid is

Answer 53

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

Question 54

The friction factor for turbulent flow in a hydraulically smooth pipe

Answer 54

depends only on Reynolds number.

Question 55

The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and

Answer 55

moving

Question 56

What causes convective acceleration in fluid flow ?

Answer 56

Non-uniformity of flow

Question 57

The Stoke’s stream function applies to the

Answer 57

cases of axial symmetry.

Question 58

Slugging in a fluidised bed can be avoided by using

Answer 58

shallow beds of solids and proper choice of particle size.

Question 59

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

Answer 59

2

Question 60

The simple pitot tube measures the __________ pressure.

Answer 60

total

Question 61

Capacity of a hydraulic accumulator is defined in terms of maximum

Answer 61

amount of energy stored.

Question 62

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

Answer 62

mean velocity

Question 63

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 &laquo_space;1, accelerating flow
b. Re&raquo_space; 1, accelerating flow
c. Re &laquo_space;1, decelerating flow
d. Re&raquo_space;1, decelerating flow

Answer 63

Re&raquo_space;1, decelerating flow

Question 64

Manometers measure the __________ pressure.

Answer 64

difference in

Question 65

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

Answer 65

Turbulent forces

Question 66

Which of the following may be termed as a variable orifice flowmeter ?

Answer 66

Rotameter

Question 67

In turbulent flow, a rough pipe has the same friction factor as a smooth pipe

Answer 67

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

Question 68

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.

Answer 68

none of these.

Question 69

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.

Answer 69

none of these.

Question 70

The capacity of an accumulator is the maximum

Answer 70

energy which it can store.

Question 71

With increase in the temperature, viscosity of a liquid

Answer 71

decreases

Question 72

Vena-contracta pressure tapping is at a distance __________ from the position of an orificemeter fitted in a pipe of internal diameter ‘d’

Answer 72

0.5 d

Question 73

The pump impeller and the turbine runner in a hydraulic torque converter

Answer 73

have different diameters.

Question 74

Reciprocating pumps compared to centrifugal pumps

Answer 74

are not subject to air binding.

Question 75

The fluid property which matters for fall-ing rain drops to acquire spherical shape is its

Answer 75

surface tension

Question 76

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).

Answer 76

all of these

Question 77

Boundary layer separation occurs when the

Answer 77

cross-section of the channel is reduced.

Question 78

The head loss in turbulent flow in a pipe varies

Answer 78

approximately as the square of the velocity.

Question 79

For flow through an orifice from a reservoir, the actual velocity at the vena con-tracta is given by

Answer 79

C.V. √2gh

Question 80

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

Answer 80

0.3

Question 81

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

Answer 81

-1

Question 82

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).

Answer 82

all of these

Question 83

Venturimeter and orificemeter measures the __________ of the fluid.

Answer 83

average velocity

Question 84

Surge tanks are provided in high pressure water pipelines to

Answer 84

reduce the water hammer.

Question 85

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.

Answer 85

small differential

Question 86

Isotropic turbulence occurs

Answer 86

where there is no velocity gradient.

Question 87

The co-efficient of drag and lift for an incompressible fluid depends on the

Answer 87

Reynolds number

Question 88

Euler’s equation of motion states, that at every point, the

Answer 88

force per unit mass equals acceleration.

Question 89

Hydraulic intensifier is used for increasing the

Answer 89

intensity of pressure of the liquid.

Question 90

In fluid flow, cavitation is caused, if the

Answer 90

flow pressure approaches its vapor pressure at the prevailing temperature.

Question 91

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. low melting point semi-solids
d. all ‘a’, ‘b’ & ‘c’

Answer 91

all of these

Question 92

Euler’s equation of motion is a statement expressing

Answer 92

conservation of mass.

Question 93

During ageing of fluid carrying pipes, the

Answer 93

absolute roughness increases linearly with time.

Question 94

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.

Answer 94

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

Question 95

Mass velocity is independent of temperature & pressure, when the flow is

Answer 95

steady and the cross-section is unchanged.

Question 96

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

Answer 96

inclined tube water.

Question 97

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

Answer 97

1/D^5

Question 98

The Navier-Stokes equation deals with the law of conservation of

Answer 98

momentum

Question 99

A differential pressure cell is used for

Answer 99

remote recording of pressure difference.

Question 100

If more than two branches of pipes are to be connected at the same point, then use a/an

Answer 100

tee

Question 101

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

Answer 101

manometric

Question 102

Acceleration head in a reciprocating pump

Answer 102

does not change the work requirement of the pump.

Question 103

The ratio of inertial forces to elastic forces is called the __________ number.

Answer 103

Mach

Question 104

Fluid flow at increasing rate through a diverging pipe is an example of __________ flow.

Answer 104

non-steady non-uniform

Question 105

The temperature in isentropic flow

Answer 105

depends on Mach number only.

Question 106

A fluid element has a velocity V = -y^2 . xi + 2yx^2 . j. The motion at (x, y) = (l/√2, 1) is

Answer 106

rotational and compressible

Question 107

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).

Answer 107

all of these

Question 108

Drag force acting on a body does not depend upon the

Answer 108

density of the body.

Question 109

Centrifugal pump is normally classified on the basis of the

Answer 109

type of casing.

Question 110

Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter ‘d’?

Answer 110

At the wall

Question 111

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

Answer 111

√T

Question 112

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

Answer 112

Q/16

Question 113

Hydraulic intensifier is used for increasing the

Answer 113

intensity of pressure of the liquid.

Question 114

In an incompressible fluid, the density is

Answer 114

not affected with moderate change in temperature & pressure.

Question 115

Check valves are used

Answer 115

for unidirectional flow.

Question 116

Velocity distribution for flow between two fixed parallel plates

Answer 116

varies parabolically across the section.

Question 117

Priming is needed in a __________ pump.

Answer 117

centrifugal

Question 118

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

Answer 118

Compressibility forces

Question 119

For ideally incompressible fluid, the Mach number will be

Answer 119

1

Question 120

A mono pump is a __________ pump.

Answer 120

positive acting rotary

Question 121

Higher specific speed (200-500) of a centrifugal pump indicates that the pump is of __________ flow type.

Answer 121

axial

Question 122

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.

Answer 122

P, Q and R

Question 123

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

Answer 123

none of these

Question 124

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

Answer 124

1/√M

Question 125

Boundary layer separation is caused by the

Answer 125

adverse pressure gradient.

Question 126

With increase in temperature, the vapor pressure of liquids

Answer 126

increases

Question 127

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.

Answer 127

17

Question 128

The ratio of wall drag to total drag in the Stoke’s law range is

Answer 128

2/3

Question 129

Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg.

Answer 129

0.01

Question 130

A pitched-blade turbine draws __________ a straight blade turbine.

Answer 130

less power than

Question 131

The most suitable flow measuring device for the fluid flow measurement in a very large diameter pipeline is a

Answer 131

pitot tube

Question 132

A centrifugal pump is called a turbine pump, if it is having a

Answer 132

vaned diffusion casing.

Question 133

Remote control valve is a __________ valve.

Answer 133

butterfly

Question 134

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.

Answer 134

Reynold number, relative roughness and head loss.

Question 135

Centre of pressure in an immersed body is __________ the centre of gravity.

Answer 135

below

Question 136

The centre of pressure is

Answer 136

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

Question 137

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

Answer 137

none of these

Question 138

In a fluidised bed reactor

Answer 138

temperature is more or less uniform.

Question 139

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

Answer 139

steady non uniform

Question 140

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).

Answer 140

all of these

Question 141

A perfect gas

Answer 141

has constant specific heat.

Question 142

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

Answer 142

pitot tube

Question 143

For a given Reynold number as d/D for an orifice increases, Cd will (where, d & D are orifice & pipe diameters respectively).

Answer 143

increase

Question 144

Speed of sound in an ideal gas depends on its

Answer 144

temperature

Question 145

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

Answer 145

less head & capacity

Question 146

If ‘x’ is the depth of flow in an open channel of large width, then the hydraulic radius is equal to

Answer 146

x

Question 147

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.

Answer 147

none of these.

Question 148

For a given fluid flow rate, which of the following incurs maximum head loss ?

Answer 148

Orifice meter

Question 149

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.

Answer 149

The fluid is incompressible.

Question 150

A fluid whose apparent viscosity increases with shear rate is termed as the __________ fluid.

Answer 150

dilatant

Question 151

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

Answer 151

Reciprocating pump

Question 152

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

Answer 152

50

Question 153

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

Answer 153

< 1

Question 154

Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have

Answer 154

higher capital &maintenance cost.

Question 155

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)

Answer 155

D = 1840 H^0.5/N

Question 156

Which of the following pipe bends will incur the largest head loss ?

Answer 156

U-bend

Question 157

Which is the most efficient and best for measuring very small flow rate of gases ?

Answer 157

Rotameter

Question 158

When the water is warm, the height to which it can be lifted by a pump

Answer 158

decreases due to reduced vapour pressure.

Question 159

Pipes having diameter 14 inches or more are designated by their

Answer 159

outside diameter

Question 160

Viscosity of water at 40°C lies in the range of

Answer 160

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

Question 161

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, the new discharge will be __________ litres/minute.

Answer 161

500

Question 162

The dimension of kinematic viscosity is

Answer 162

L^2T^-1

Question 163

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

Answer 163

10 m/sec

Question 164

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

Answer 164

none of these

Question 165

Lower BWG means __________ of the tube.

Answer 165

lower cross-section

Question 166

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.

Answer 166

parabolic

Question 167

The Prandtl mixing length is

Answer 167

useful for computing laminar flow problems.

Question 168

N^2Re/NFr is called the __________ number.

Answer 168

Galileo

Question 169

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)

Answer 169

2y/3

Question 170

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 &laquo_space; 1

Answer 170

increases linearly with V.

Question 171

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).

Answer 171

all of these

Question 172

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)

Answer 172

all of these

Question 173

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

Answer 173

none of these

Question 174

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’?

Answer 174

8 . Vavg/D

Question 175

Pascal’s law is valid, only when the fluid is

Answer 175

at rest.

Question 176

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 m^3/s? The Fanning friction factor, f is 0.0062.

Answer 176

11 m

Question 177

The pressure head of a flow meter remains constant for

Answer 177

rotameter

Question 178

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).

Answer 178

all of these

Question 179

A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double

Answer 179

discharge

Question 180

Which of the following is used for very accurate measurement of flow of gas at low velocity ?

Answer 180

Hot wire annemometer

Question 181

In Newton’s law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is

Answer 181

0.44

Question 182

A pressure of 10 m head of water is equivalent to __________ kN/m2.

Answer 182

98

Question 183

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

Answer 183

200

Question 184

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

Answer 184

2

Question 185

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.

Answer 185

logarithmic

Question 186

Maintenance cost of a __________ pump for a particular duty is the least.

Answer 186

centrifugal

Question 187

Choking in case of pipe flow means that a

Answer 187

specified mass flow rate can not be achieved.

Question 188

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

Answer 188

electrical conductivity

Question 189

The nominal size of a hose pipe is specified by its

Answer 189

I.D.

Question 190

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).

Answer 190

all of these.

Question 191

For flow of fluids through packed bed, the superficial velocity is

Answer 191

less than the average velocity through channels.

Question 192

Cd is always __________ Cc.

Answer 192

greater than

Question 193

Buoyant force

Answer 193

depends on the weight of the floating body.

Question 194

Which of the following is an undesirable property of a manometric liquid ?

Answer 194

High vapour pressure.

Question 195

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

Answer 195

manometric

Question 196

The speed of sound in an ideal gas varies as the

Answer 196

temperature

Question 197

The maximum head that can be developed by a single impeller is __________ ft.

Answer 197

250-300

Question 198

The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is

Answer 198

< 1

Question 199

The general relationship between speed N, head H, power P and discharge Q for a centrifugal pump is

Answer 199

Q∝N : H∝N^2 : P∝N^3

Question 200

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 ?

Answer 200

2

Question 201

Foot valve provided in the pump is a __________ valve.

Answer 201

back pressure

Question 202

The discharge co-efficient for an orificemeter does not depend upon the

Answer 202

pipe length.

Question 203

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).

Answer 203

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

Question 204

An equipotential line is __________ to the velocity vector at every point.

Answer 204

normal

Question 205

Path followed by water jet issuing from the bottom of a water tank will be a

Answer 205

parabola (vertex being at the opening).

Question 206

Which of the following produces maximum pressure difference for transportation of gases ?

Answer 206

Compressors

Question 207

Drag co-efficient in hindered settling is __________ that in free settling.

Answer 207

always greater than

Question 208

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

Answer 208

66.6

Question 209

One dimensional fluid flow implies the

Answer 209

flow in which transverse components are zero.

Question 210

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

Answer 210

all of these

Question 211

Hydraulic radius is the ratio of

Answer 211

flow area to wetted perimeter.

Question 212

The unit of bulk modulus of elasticity for a liquid in S.I. unit is

Answer 212

N/m^2

Question 213

Power requirement of fans having constant wheel diameter varies __________ fan speed.

Answer 213

as cube of

Question 214

In the low Reynolds number region, the drag force on a sphere is proportional to

Answer 214

V

Question 215

The continuity equation

Answer 215

represents the conservation of mass.

Question 216

Experimental study of laminar fluid flow through a circular tube was conducted by

Answer 216

Hagen and Poiseuille

Question 217

The most economical flow control valve for use with large diameter pipes is a

Answer 217

butterfly valve

Question 218

Each term in Bernaulli’s equation represents the __________ of the fluid.

Answer 218

energy per unit weight

Question 219

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

Answer 219

None of these

Question 220

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

Answer 220

5.657

Question 221

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

Answer 221

increase.

Question 222

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

Answer 222

R^4

Question 223

Interstage coolers are provided in a multistage compressor to

Answer 223

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

Question 224

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).

Answer 224

all of these

Question 225

Reynolds number is the ratio of

Answer 225

inertial forces to viscous forces.

Question 226

The discharge through a venturimeter depends upon

Answer 226

pressure drop only.

Question 227

N. second/m^2 is

Answer 227

the S.I. unit of dynamic viscosity.

Question 228

The distance between metacentre and __________ is called metacentric height.

Answer 228

centre of gravity

Question 229

Check valve is used for __________ flow.

Answer 229

unidirectional

Question 230

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).

Answer 230

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

Question 231

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

Answer 231

brings about no further reduction of

Question 232

Power number is the ratio of

Answer 232

drag stress to inertial stress.

Question 233

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

Answer 233

none of these

Question 234

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

Answer 234

venturimeter

Question 235

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

Answer 235

gate valve

Question 236

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

Answer 236

avoid priming, every time we start the pump.

Question 237

An ideal fluid is

Answer 237

frictionless & incompressible.

Question 238

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

Answer 238

pressure drop is almost constant.

Question 239

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

Answer 239

weight of the liquid displaced.

Question 240

In case of end to end connection of two or more pipes in series, the __________ each pipe.

Answer 240

same rate of flow passes through

Question 241

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

Answer 241

Blake-Pllummer equation

Question 242

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

Answer 242

specific volume

Question 243

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.

Answer 243

thick molten soap at 80°C.

Question 244

A stream line is

Answer 244

fixed in space in steady flow.

Question 245

Quicksand is an example of a __________ fluid.

Answer 245

dilatent

Question 246

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

Answer 246

> 12.5

Question 247

Differential manometer measures the

Answer 247

pressure difference

Question 248

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

Answer 248

directly as

Question 249

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

Answer 249

√d

Question 250

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

Answer 250

steady non-uniform

Question 251

The line of action of the buoyant force acts through the

Answer 251

centroid of the displaced volume of fluid.

Question 252

Cavitation in a centrifugal pump can be avoided by keeping the

Answer 252

inlet pressure high

Question 253

Vane anemometer

Answer 253

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

Question 254

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

Answer 254

12.4

Question 255

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

Answer 255

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

Question 256

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.

Answer 256

transition

Question 257

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.

Answer 257

Steadily decreasing flow through a reducing section.

Question 258

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

Answer 258

four

Question 259

Terminal velocity is

Answer 259

a constant velocity with no acceleration.

Question 260

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.

Answer 260

f1 > f2

Question 261

For an incompressible fluid, the bulk modulus of elasticity is

Answer 261

∞ N/m^2

Question 262

A fluid is a substance, that

Answer 262

flows when even a small shear is applied to it.

Question 263

The pressure intensity is the same in all directions at a point in a fluid

Answer 263

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

Question 264

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.

Answer 264

II, III, V

Question 265

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 ?

Answer 265

< 0.3

Question 266

Boundary layer exists in flow

Answer 266

of real fluids.

Question 267

Rubber latex is an example of __________ fluid.

Answer 267

pseudoplastic

Question 268

The frictional resistance in laminar flow does not depend on the

Answer 268

area of surface in contact.

Question 269

A venturimeter measures the
a. velocity head
b. pressure
c. point velocity
d. none of these

Answer 269

none of these

Question 270

Gradually varying fluid flow is an example of __________ flow.

Answer 270

non-steady uniform

Question 271

Drag is the force component exerted on an immersed object,

Answer 271

the component being parallel to theflow direction.

Question 272

To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump.

Answer 272

reciprocating

Question 273

Cocks are used to control

Answer 273

any liquid

Question 274

The dimension of surface tension is

Answer 274

MT^-2

Question 275

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.

Answer 275

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

Question 276

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.

Answer 276

none of these.

Question 277

Rubber latex is an example of a __________ .fluid.

Answer 277

pseudoplastic

Question 278

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

Answer 278

None of these

Question 279

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

Answer 279

cavitation

Question 280

Working of a __________ pump characterises mixed flow.

Answer 280

turbine

Question 281

The rate of change of moment of momentum represents the __________ by the fluid.

Answer 281

torque applied

Question 282

Cd for the orifice plate varies from

Answer 282

0.58 to 0.8

Question 283

The discharge through a V-notch weir varies as

Answer 283

H^5/2

Question 284

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

Answer 284

pitot tube

Question 285

The specific speed of a pump is defined as the speed of a unit of such a size, that it

Answer 285

delivers unit discharge at unit head.

Question 286

In case of venturimeters, friction losses are about __________ percent of maximum velocity head.

Answer 286

2

Question 287

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)

Answer 287

all of these

Question 288

Turbine impeller

Answer 288

is effective over wide range of viscosities.

Question 289

Friction produced by the formation of wakes is called the __________ friction.

Answer 289

form

Question 290

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

Answer 290

ηm = ηv . ηma

Question 291

When the pipe Reynold’s number is 6000, the flow is generally

Answer 291

turbulent

Question 292

With a constant diameter impeller of a centrifugal pump

Answer 292

head varies as the square of speed.

Question 293

For water, when the pressure increases, the viscosity

Answer 293

first decreases, and then increases

Question 294

Location of vena-contracta in an orificemeter does not depend upon the

Answer 294

type of orifice.

Question 295

At low Reynolds number

Answer 295

viscous forces control and inertial forces are unimportant.

Question 296

For laminar flow through a closed conduit

Answer 296

Vmax = 2Vav

Question 297

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.

Answer 297

square root

Question 298

Unsteady uniform flow is represented by flow through a/an

Answer 298

long pipe at decreasing rate.

Question 299

If Blausius or Darcey friction factor is ‘f1’ then the Fanning friction factor is equal to

Answer 299

f1/4

Question 300

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.

Answer 300

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

Question 301

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

Answer 301

L ρv2/D

Question 302

While starting a centrifugal pump, its delivery valve should be kept

Answer 302

closed.

Question 303

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

Answer 303

x

Question 304

Sewage sludge is an example of the __________ fluid.

Answer 304

Bingham plastic

Question 305

Multistage centrifugal pumps are generally used for

Answer 305

high head.

Question 306

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

Answer 306

0.766

Question 307

A bed consists of particles of density 2000 kg/m^3. 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

Answer 307

11.77 kPa

Question 308

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ?

Answer 308

Develops high pressure

Question 309

For a specific centrifugal air blower operating at constant speed & capacity, the power requirement and pressure vary

Answer 309

directly as gas density.

Question 310

Capillary tube method of viscosity measurement is based on the

Answer 310

Hagen-Poiseulle’s equation

Question 311

It is possible to integrate an automatic flow controller to a

Answer 311

rotameter

Question 312

For liquid flow through a packed bed, the superficial velocity as compared to average velocity through the channel in the bed is

Answer 312

less

Question 313

For a reciprocating pump, the indicator diagram is the graph between the

Answer 313

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

Question 314

High specific speed of a pump implies that, it is a/an __________ pump.

Answer 314

axial flow

Question 315

A gas (density = 1.5 kg/m^3 , 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/m^3and viscosity of 3 x 10^-5kg/m.s flowing at 3 m/s will be

Answer 315

12600 Pa/m

Question 316

One poise (unit of absolute/dynamic viscosity) is equivalent to one

Answer 316

gm/cm. sec.

Question 317

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

Answer 317

Nikuradse

Question 318

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 ?

Answer 318

0.64

Question 319

For an unstable equilibrium of a floating body (where, M = metacentre.)

Answer 319

M is below G

Question 320

Which of the following can be used for the direct measurement of volumetric flow rate of slurry ?

Answer 320

Rotameter

Question 321

A pipe is defined as ‘hydraulically smooth’, if the friction factor

Answer 321

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

Question 322

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

Answer 322

28.2

Question 323

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)

Answer 323

all of these

Question 324

In case of a __________ the energy of flow is considerably decreased downstream of the machine.

Answer 324

turbine

Question 325

With increase in the shear rate, the apparent viscosity of pseudoplastic fluids

Answer 325

decreases

Question 326

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

Answer 326

0.62

Question 327

Purpose of hydraulic accumulator is to

Answer 327

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

Question 328

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.

Answer 328

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

Question 329

Purpose of relief valve in a reciprocating pump is to

Answer 329

protect the pump against developing excessive pressure.

Question 330

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.

Answer 330

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

Question 331

In case of turbulent flow of fluid through a circular pipe, the

Answer 331

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

Question 332

What is the maximum theoretical suction lift (metres) of a reciprocating pump ?

Answer 332

10

Question 333

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.

Answer 333

2

Question 334

Function of air vessel provided in a reciprocating pump is to

Answer 334

reduce discharge fluctuation.

Question 335

The Prandtl pitot tube measures the

Answer 335

velocity at a point in the flow.

Question 336

Pressure drop in packed bed for turbulent flow is given by the __________ equation.

Answer 336

Blake-Plummer

Question 337

In the complete turbulence zone (in rough pipes), the

Answer 337

friction factor is independent of the relative roughness.

Question 338

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

Answer 338

Water at room temperature

Question 339

In case of centrifugal fan or blower, the gas capacity varies as

Answer 339

speed

Question 340

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.

Answer 340

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

Question 341

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.

Answer 341

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

Question 342

The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is

Answer 342

parabolic near the wall and flat in the middle.

Question 343

Mach number is the ratio of the speed of the

Answer 343

fluid to that of the sound.

Question 344

A piezometer opening measures the __________ fluid pressure.

Answer 344

undisturbed

Question 345

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

Answer 345

constant

Question 346

The unit of dynamic viscosity in SI unit is

Answer 346

kg/m . sec

Question 347

Pressure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as

Answer 347

V^2

Question 348

Dean number is concerned with the

Answer 348

fluid flow through helical pipes.

Question 349

The equation given below is called the __________ .
F^-0.5 = 4.07 loge (NRe√f)^-0.6

Answer 349

Von-Karman equation

Question 350

Poise is converted into stoke by

Answer 350

dividing by density (gm/c.c).

Question 351

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.

Answer 351

dilatant

Question 352

Kinetic energy of fluid per unit weight represented by the velocity head is given by

Answer 352

v^2/2gc

Question 353

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)

Answer 353

all of these

Question 354

The pressure co-efficient is the ratio of pressure forces to __________ forces.

Answer 354

viscous

Question 355

Vena-contracta formed during flow of a liquid through an orificemeter has

Answer 355

minimum liquid cross-section.

Question 356

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)

Answer 356

μ

Question 357

Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will __________ the gas discharge pressure.

Answer 357

increase

Question 358

In continuous fluidisation

Answer 358

solids are completely entrained.

Question 359

Glass pipes can be joined by

Answer 359

bell and spigot joint

Question 360

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

Answer 360

greater in 0.5 mm dia tube.

Question 361

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

Answer 361

2

Question 362

Weber number is the ratio of inertial force to __________ force.

Answer 362

surface tension

Question 363

The curve of metacentre for a floating body __________ the curve of buoyancy.

Answer 363

is the evolute of

Question 364

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 ?

Answer 364

40° and 140°

Question 365

The range of a particular rotameter can be increased by

Answer 365

use of floats of different densities.

Question 366

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

Answer 366

Fanning friction factor

Question 367

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.

Answer 367

660

Question 368

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

Answer 368

vacuum

Question 369

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 ?

Answer 369

0.7

Question 370

Dimension of kinematic viscosity is

Answer 370

L^2 . T^-1

Question 371

A streamline is a line in flow field,

Answer 371

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

Question 372

While starting an axial flow pump, its delivery valve should be kept

Answer 372

closed

Question 373

__________ forces do not act in case of fluid flow.

Answer 373

Tensile

Question 374

Non-colloidal solution is an example of the __________ fluid.

Answer 374

Newtonion

Question 375

Boundary layer separation is caused by the

Answer 375

adverse pressure gradient.

Question 376

Identification of pipelines carrying different liquids and gases is done by the __________ of the pipe.

Answer 376

colour

Question 377

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.

Answer 377

A Newtonion fluid obeys Newton’s law of cooling.

Question 378

What is the unit of kinematic viscosity in SI unit ?

Answer 378

M^2/sec

Question 379

Hydraulic __________ works on the principle of Pascal’s law of transmission of fluid pressure.

Answer 379

press

Question 380

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

Answer 380

> Δp

Question 381

The contraction co-efficient for Borda’s mouthpiece (for frictionless fluid) is

Answer 381

0.5

Question 382

Purpose of air lift pump is to

Answer 382

lift water from a well by using compressed air.

Question 383

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.

Answer 383

none of these.

Question 384

For very low pressure and high discharge rate, the compressor used is a/an __________ compressor.

Answer 384

rotary

Question 385

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.

Answer 385

gear

Question 386

What is the speed of sound (m/sec) in ordinary water ?

Answer 386

1500

Question 387

Two piping system are said to be equivalent, when the __________ are same.

Answer 387

fluid flow rate & friction loss

Question 388

Potential function is applicable only for __________ flow.

Answer 388

irrotational

Question 389

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

Answer 389

Fluid flow at the inlet to a nozzle

Question 390

Volute of a centrifugal pump should be designed in a fashion, such that the

Answer 390

kinetic head gets converted into static head.

Question 391

The head loss due to sudden contraction is proportional to

Answer 391

velocity head

Question 392

Cavitation occurs in a centrifugal pump when the suction pressure is

Answer 392

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

Question 393

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 ?

Answer 393

Sewage sludge

Question 394

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).

Answer 394

all of these

Question 395

Which law is followed by the velocity distribution in the turbulent boundary layer?

Answer 395

Logarithmic law

Question 396

The losses in open channel flow generally vary as the

Answer 396

first power of the roughness.

Question 397

Out of the following flow measuring devices, which one incurs the maximum installation cost as well as pressure loss ?

Answer 397

Venturimeter

Question 398

For turbulent fluid flow in pipe, the expression for Prandtl one seventh power law is (where, r = pipe radius, x = distance).

Answer 398

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

Question 399

Which of the following has the maximum compression ratio ?

a. Blower
b. Compressor
c. Vacuum pump
d. Fan

Answer 399

Vacuum pump

Question 400

Scale up of agitator design requires

Answer 400

all geometrical, dynamic and kinematic similarity.

Question 401

The actual velocity at vena-contracta for flow through an orifice from a reservoir is given by

Answer 401

Cv . √2gH

Question 402

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

Answer 402

V^2

Question 403

Unsteady non-uniform flow is represented by flow through a/an

Answer 403

expanding tube at increasing rate.

Question 404

Prandtl number is a measure of the

Answer 404

heat conduction to viscosity of a fluid.

Question 405

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

Answer 405

2

Question 406

In hindered settling, the particles are

Answer 406

near each other,

Question 407

A globe valve is the most suitable for applications, in which

Answer 407

fluid flow control is required.

Question 408

__________ isused for measuring the static pressure exerted on the wall by a fluid flowing parallel to the wall in a pipeline.

Answer 408

Pitot tube

Question 409

One stoke (unit of kinematic viscosity) is equivalent to

Answer 409

1 cm^2/second

Question 410

Air vessel of a reciprocating pump is initially filled with

Answer 410

compressed air

Question 411

The ratio of inertial forces to gravity forces is called the __________ number.

Answer 411

Froude

Question 412

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

Answer 412

N^3D^5

Question 413

Equivalent length of a pipe fitting is

Answer 413

dependent on Reynolds number.

Question 414

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

Answer 414

n-m

Question 415

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

Answer 415

Newtonion

Question 416

Existence of boundary layer in fluid flow is because of the

Answer 416

fluid viscosity

Question 417

In case of laminar flow of fluid through a circular pipe, the

Answer 417

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

Question 418

Which of the following facilitates close control of flow of fluids ?
a. Gate valve
b. Globe valve
c. Butterfly valve
d. Check valve

Answer 418

Globe valve

Question 419

Stoke’s equation is valid in the Reynolds number range

Answer 419

0.01 to 0.1

Question 420

When a fluid flows over a solid surface, the

Answer 420

velocity gradient is zero at the solid surface.

Question 421

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

Answer 421

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

Question 422

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

Answer 422

4000

Question 423

The velocity for subsonic flow in a pipeline

Answer 423

increases in the downstream direction.

Question 424

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

Answer 424

10

Question 425

The ratio of pressure forces to inertial forces is called the __________ number.

Answer 425

Euler

Question 426

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

Answer 426

A, B, E

Question 427

Cavitation in a centrifugal pump results from

Answer 427

low barometric pressure

Question 428

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

Answer 428

1

Question 429

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

Answer 429

5π/2

Question 430

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

Answer 430

none of these.

Question 431

What is the value of Fanning friction factor f ‘ for smooth pipe at NRe = 106 approximately ?

Answer 431

0.003

Question 432

Air vessel provided in a reciprocating pump is for

Answer 432

making the friction in pipe uniform.

Question 433

A hydraulic accumulator comprises of

Answer 433

a cylinder and a plunger.

Question 434

Bernoulli’s equation for steady, frictionless, continuous flow states that the __________ at all sections is same.

Answer 434

total energy

Question 435

A tube is specified by its

Answer 435

thickness & outer diameter both

Question 436

Prandtl mixing length is

Answer 436

zero at the pipe wall.

Question 437

The hydraulic diameter of an annulus of inner and outer radii Ri and Ro respectively is

Answer 437

2(Ro-Ri)

Question 438

Ratio of inertial forces to surface tension forces is called the __________ number.

Answer 438

Weber

Question 439

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

Answer 439

1.84

Question 440

The ratio of inertial forces to viscous forces is called the __________ number.

Answer 440

Reynold

Question 441

Enamels and paints are generally __________ fluid.

Answer 441

pseudo-plastic

Question 442

With the increase in depth, the hydrostatic pressure in an unaccelerated incompressible fluid (in a constant gravitational field)

Answer 442

increases linearly.

Question 443

Flow measurement in an open channel is done by a/an

Answer 443

weir

Question 444

Newton’s law of viscosity relates the

Answer 444

shear stress and rate of angular deformation in a fluid.

Question 445

The equivalent diameter for fluid flow through square cross section channel of side ‘x’, for pressure drop calculation purpose is given by

Answer 445

x

Question 446

Hydraulic radius of 6” x 12” cross-section, is __________ inches.

Answer 446

2

Question 447

Baffles in mixing tanks are provided to

Answer 447

reduce swirling and vortex formation.

Question 448

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

Answer 448

Kozney - Karman equation

Question 449

Forces acting on a particle settling in fluid are __________ forces.

Answer 449

gravitational or centrifugal buoyant drag.

Question 450

For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the

Answer 450

square of the radial distance.

Question 451

In a dry packed bed, the pressure drop will be changed by increasing the flow rate as

Answer 451

V^1.8

Question 452

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

Answer 452

none of these

Question 453

Navier-Stokes equation is useful in the analysis of __________ fluid flow problems.

Answer 453

viscous

Question 454

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

Answer 454

0.95

Question 455

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

Answer 455

airlift

Question 456

Two fluids are flowing through two similar pipes of the same diameter. The Reynold’s number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will

Answer 456

decrease

Question 457

What is the value of co-efficient of discharge for square edged circular orifice (for β = 0.3 to 0.5) ?

Answer 457

0.61 - 0.63

Question 458

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

Answer 458

0.1

Question 459

Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its

Answer 459

neither inner nor outer diameter

Question 460

I.D. of 1/4” schedule 40 pipe is 0.364”. I.D. of a 1/2” schedule 40 pipe would be __________ inch

Answer 460

0.5

Question 461

Two liquids manometer is used for measuring small pressure differences in

Answer 461

gases

Question 462

A piezometer provided in the pipe measures

Answer 462

static pressure

Question 463

The pump used for irrigation purposes is generally designed for

Answer 463

large capacity & low head.

Question 464

In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes

Answer 464

less than liquid vapor pressure.

Question 465

Pressure gradient in the pipe flow is influenced by the

a. diameter of pipe.
b. velocity of the fluid.
c. density & viscosity of the fluid.
d. all (a), (b) and (c).

Answer 465

all of these

Question 466

__________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2.

Answer 466

Plunger

Question 467

Boiler feed water pump is usually a __________ pump.

Answer 467

multistage centrifugal

Question 468

Viscosity of a liquid decreases __________ with rise in temperature.

Answer 468

logarithmically

Question 469

In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is

Answer 469

the velocity of sound.

Question 470

Discharge in laminar flow through a pipe varies

Answer 470

as the square of the radius.

Question 471

The lift of a ballon is

Answer 471

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

Question 472

In which of the following body shapes, the pressure drag is large compared to the friction drag ?

a. Stream line body
b. Two dimensional body
c. Bluff body
d. None of these

Answer 472

Bluff body

Question 473

Major loss in sudden contraction in pipe flow is due to

Answer 473

flow contraction.

Question 474

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

Answer 474

Blower

Question 475

The ratio of actual discharge to theoretical discharge through an orifice is equal to

Answer 475

Cc . Cv

Question 476

A free jet of water of cross-sectional area 0.01m^2 and a velocity of 20 m/s strikes a plate and then flows in a plane parallel to the plate as shown in the figure below. The horizontal component of the force on the support is

Answer 476

4000 N

Question 477

Cp/Cv is termed as

Answer 477

adiabatic constant

Question 478

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

Answer 478

Non-colloidal solution

Question 479

Which of the following valves will incur maximum pressure drop for the same discharge of water ?

a. Globe valve
b. Gate valve
c. Needle valve
d. Butterfly valve

Answer 479

Needle valve

Question 480

Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor.

Answer 480

more than

Question 481

In deriving Bernoulli’s equation, fluid is assumed to be

Answer 481

incompressible, frictionless, steady, along a streamline.

Question 482

Unit of mass velocity is

Answer 482

kg/m^2. hr

Question 483

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

Answer 483

decrease

Question 484

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

Answer 484

12.6 H

Question 485

The boundary layer thickness at a given section along a flat plate __________ with increasing Reynold’s number.

Answer 485

decreases

Question 486

Low specific speed of a pump implies that, it is a/an __________ pump.

Answer 486

centrifugal

Question 487

For pumping slurry, one can use a __________ pump.

Answer 487

diaphargm

Question 488

Bernoulli’s equation describes the

Answer 488

mechanical energy balance in potential flow.

Question 489

Which law/principle of solid mechanics is similar/equivalent to Newton’s law of viscosity in fluid mechanics ?

Answer 489

Hooke’s law.

Question 490

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

Answer 490

spouted

Question 491

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

Answer 491

all of these

Question 492

Potential flow is characterised by the

Answer 492

irrotational and frictionless flow.

Question 493

For the production of very high vacuum, a __________ pump is normally used.

Answer 493

diffusion

Question 494

In parallel pipe problems, the

Answer 494

head loss is the same through each pipe.

Question 495

Fluid flow through a packed bed is represented by the __________ equation.

Answer 495

Ergun’s

Question 496

__________ is an example of axial flow impeller.

Answer 496

Propeller

Question 497

Froude number is not a factor

Answer 497

when there is no vortex formation.

Question 498

If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor).

Answer 498

Q = Q1 + Q2 + Q3

Question 499

Horsepower requirement for given pump capacity depends upon the

a. specific gravity of the liquid
b. suction lift
c. discharge head
d. all (a), (b) and (c)

Answer 499

all of these

Question 500

Bernoulli’s equation accounts for the

Answer 500

different forms of mechanical energy

Question 501

__________ pumps are a group of vacuum pumps.

Answer 501

Hyter

Question 502

Plunger pumps are used for

Answer 502

higher pressure

Question 503

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

Answer 503

0.5

Question 504

In turbulent flow, the

Answer 504

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

Question 505

Momentum correction factor used in fluid flow problems accounts for the

Answer 505

non uniform direction of velocities at inlet & outlet sections.

Question 506

Design of the casing of centrifugal pump should be such as to minimise the

Answer 506

loss of kinetic head

Question 507

Which of the following is used for pumping crude oil from oil well ?

a. Single stage centrifugal pump
b. Gear pump
c. Screw pump
d. Duplex/triplex reciprocating pump

Answer 507

Duplex/triplex reciprocating pump

Question 508

The energy loss in flow through ven-turimeter is less than that through flow nozzle, because in case of a flow nozzle, the

Answer 508

sudden expansion of flow in the downstream occurs.

Question 509

__________ flow means the flow of incompressible fluid with no shear.

Answer 509

Potential

Question 510

The continuity equation

Answer 510

relates mass flow rate along a stream tube.

Question 511

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

Answer 511

directly proportional to square of

Question 512

Pressure drop in a packed bed for laminar flow is given by the __________ equation.

Answer 512

Kozney-Karman

Question 513

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

Answer 513

pseudoplastic

Question 514

Stoke’s law is valid, when NRe, p is less than

Answer 514

2

Question 515

Froude number is the ratio of

Answer 515

inertial stress to gravitational stress.

Question 516

Normal depth in open channel flow is the depth of flow in the channel

Answer 516

corresponding to uniform flow.

Question 517

Which of the following flow measuring devices is an area meter ?
a. Venturimeter
b. Orifice meter
c. Anemometer
d. Rotameter

Answer 517

Rotameter

Question 518

With decrease in particle size to be fluidised by a particular fluid, the operating range of fluidisation velocity

Answer 518

does not change

Question 519

Diaphragm valves are used for handling __________ fluids.

Answer 519

corrosive

Question 520

The schedule number of a pipe is an indication of its

Answer 520

wall thickness

Question 521

Minimum porosity for fluidisation is

Answer 521

the porosity of the bed when true fluidisation begins.

Question 522

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

Answer 522

decrease

Question 523

Steady non-uniform flow is exemplified by flow through a/an

Answer 523

expanding tube at constant rate.

Question 524

The maximum depth from which a centrifugal pump can draw water is

Answer 524

34 feet.

Question 525

Hot wire anemometer is used to measure the

Answer 525

velocity of gases.

Question 526

Propeller type centrifugal pumps are most suitable for

Answer 526

high capacity at low heads.

Question 527

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

Answer 527

Newtonion

Question 528

Momentum transfer in laminar flow of fluids results due to the

Answer 528

velocity gradient

Question 529

The capillary rise of mercury is maximum in glass tube of dia __________ mm.

Answer 529

0.5

Question 530

Diaphragm pumps are used to transport

Answer 530

slurries

Question 531

For steady ideal fluid flow, the Bernoulli’s equation states that the

Answer 531

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

Question 532

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

Answer 532

all of these

Question 533

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

Answer 533

100

Question 534

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

Answer 534

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

Question 535

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

Answer 535

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

Question 536

The most serious disadvantage of an orificemeter is that

Answer 536

most of the pressure drop is not recoverable.

Question 537

The discharge through a rectangular weir varies as

Answer 537

H^3/2

Question 538

In case of supersonic flow of a fluid through pipeline, the ‘Mach number’ is

Answer 538

> 1

Question 539

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, the power consumed now will be __________ hp.

Answer 539

0.5

Question 540

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

Answer 540

50

Question 541

Disc compensators are provided in large diameter fuel gas carrying pipelines to

Answer 541

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

Question 542

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

Answer 542

125.6

Question 543

Paper pulp is an example of __________ fluid.

Answer 543

bingham plastic

Question 544

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

Answer 544

0.95

Question 545

A conical tank with a bottom opening of cross-sectional area A is filled with water and is mounted on supports as shown in the figure. What is the force F with which plate X must be pushed up to prevent water from leaking ? Assume that the density of air is negligible as compared to the density of water ρL. (1)

Answer 545

ρL . A.Hg

Question 546

A relief valve

Answer 546

is a directional control valve.

Question 547

An isentropic process is the one, in which

Answer 547

pvr = constant, and process is reversible

Question 548

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

Answer 548

linear with radius for both laminar & turbulent flow.

Question 549

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

Answer 549

more

Question 550

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

Answer 550

dynamic similarity

Question 551

Air vessel fitted to a reciprocating pump

Answer 551

decreases the work done.

Question 552

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

Answer 552

occurs when NRe is very small.

Question 553

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

Answer 553

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

Question 554

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

Answer 554

55

Question 555

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

Answer 555

greater than the vapour pressure of the liquid.

Question 556

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

Answer 556

all of these

Question 557

In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow?

Answer 557

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

Question 558

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

Answer 558

unsteady

Question 559

The __________ pressure is measured by a static tube.

Answer 559

static

Question 560

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

Answer 560

an elementary wave in an open channel.

Question 561

Mercury is an ideal barometric fluid mainly due to its

Answer 561

very low vapor pressure.

Question 562

A spherical particle is falling slow in a viscous liquid such that Reynolds number is less than 1. Which statement is correct for this situation ?

Answer 562

Drag, gravitational and buoyancy forces are impportant.

Question 563

A gas

Answer 563

is a supercritical vapor.

Question 564

Pitot tube measures the __________ of a fluid.

Answer 564

point velocity

Question 565

Which of the following is not dimension-less?
a. Froude number
b. Kinematic viscosity
c. Pressure co-efficient
d. None of these

Answer 565

Kinematic viscosity

Question 566

In laminar flow through a round tube, the discharge varies

Answer 566

inversely as the viscosity.

Question 567

Which is not a variable head meter ?

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

Answer 567

Rotameter

Question 568

The pipe wall thickness is minimum for a pipe of given nominal size having schedule number

Answer 568

40

Question 569

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

Answer 569

1000

Question 570

Centrifugal pumps as compared to reciprocating pumps

Answer 570

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

Question 571

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

Answer 571

Angular deformation

Question 572

In which type of fluid flow, the velocity of flow of fluid changes from point to point in the fluid at any instant ?

Answer 572

Non-uniform

Question 573

The continuity equation in ideal fluid flow states that

Answer 573

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

Question 574

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

Answer 574

all of these.

Question 575

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

Answer 575

x

Question 576

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid

Answer 576

is independent of the specific weight of the fluid.

Question 577

Drag co-efficient for flow past immersed body is the ratio of __________ to the product of velocity head and density.

Answer 577

average drag per unit projected area

Question 578

Creeping flow around a sphere is defined, when particle Reynolds number is

Answer 578

< 0.1

Question 579

Open channel liquid flow is most conveniently measured by a

Answer 579

notch

Question 580

Toothpaste is a

Answer 580

dilatent

Question 581

Slurries can be most conveniently pumped by a __________ pump.

Answer 581

centrifugal

Question 582

Volute type of casing is provided in a centrifugal pump to

Answer 582

increase the discharge.

Question 583

In a free vortex, the

Answer 583

velocity changes linearly with radial distance.

Question 584

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

Answer 584

The eddy viscosity is a fluid property.

Question 585

The velocity distribution in direction normal to the direction of flow in plane Poiseuille flow is

Answer 585

parabolic

Question 586

In fluid flow, the stagnation point is defined as a point, where the __________ is zero.

Answer 586

flow velocity

Question 587

A special type of liquid transporting device is the diffuser pump, in which __________ are minimised.

Answer 587

shock losses

Question 588

Which of the following is most prone to pulsating discharge flow ?

Answer 588

Gear pump

Question 589

A streamline is

Answer 589

drawn normal to the velocity vector at every point.

Question 590

Which of the following relationship is valid for the equilibrium position of the float in a rotameter ?(where, Df= Drag force on the float Bf = Buoyant force on the float Wf = Weight of the float)

Answer 590

Df + Bf = Wf

Question 591

Drag is defined as the force exerted by the

Answer 591

fluid on the solid in the direction of flow.

Question 592

The boundary layer is that part of a moving fluid, in which the fluid velocity is

Answer 592

affected by the presence of a solid boundary.

Question 593

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

Answer 593

all of these

Question 594

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

Answer 594

ε = ε0 + α.t

Question 595

Nominal size of a pipe is an indication of its __________ diameter.

Answer 595

approximate

Question 596

Fluidised beds are formed, when the

Answer 596

gravity force is less than the fluid friction.

Question 597

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

Answer 597

1

Question 598

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

Answer 598

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

Question 599

Medium viscosity lubricating oil can be most ideally pumped by a __________ pump.

Answer 599

vane

Question 600

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

Answer 600

d^2.5

Question 601

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

Answer 601

electromagnetic

Question 602

Small pressure differences in liquids is measured using a/an

Answer 602

inclined tube manometer.

Question 603

With increase in pump speed, its NPSH requirement

Answer 603

increases

Question 604

In the Newton’s law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass is __________ the fluid viscosity.

Answer 604

inversely proportional to

Question 605

Gear pump

Answer 605

is a positive displacement pump.

Question 606

Most of the centrifugal pumps used in chemical plants are usually __________ driven.

Answer 606

electric motor

Question 607

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the

Answer 607

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

Question 608

Venturimeters, orificemeters and nozzles are used to measure the fluid discharge from a pipeline. The average fluid velocity in a pipeline can be measured by a/an

Answer 608

hot wire anemometer

Question 609

The time taken for gravity flow of a fixed volume of liquid (as in Redwood viscometer) is directly proportional to its

Answer 609

ratio of absolute viscosity to density.

Question 610

Sewage sludge is __________ type of non-Newtonion fluid.

Answer 610

Bingham plastic

Question 611

Ratio of pressure and inertia force gives __________ number.

Answer 611

Euler

Question 612

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

Answer 612

10 .

Question 613

Volume of liquid displaced by a floating body is equivalent to its

Answer 613

own weight

Question 614

The __________ is measured by a piezometric opening.

Answer 614

total pressure

Question 615

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

Answer 615

Siphon

Question 616

Steady uniform flow is represented by flow through a/an

Answer 616

long pipe at constant rate.

Question 617

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

Answer 617

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

Question 618

Cavitation can be prevented by

Answer 618

maintaining the suction head sufficiently greater than the vapour pressure.

Question 619

Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will

Answer 619

increase

Question 620

Steady flow occurs, when the

Answer 620

conditions do not change with time at any point.

Question 621

With increase in the ratio of orifice diameter to pipe diameter, the fraction of the orifice pressure differential that is permanently lost

Answer 621

decreases

Question 622

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

Answer 622

Head & discharge

Question 623

The kinetic energy correction factor for velocity distribution of laminar flow is

Answer 623

1.66

Question 624

Priming of a centrifugal pump is done to

Answer 624

avoid chances of separation inside the impeller.

Question 625

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

Answer 625

60

Question 626

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

Answer 626

union

Question 627

A fluid is the one, which

Answer 627

cannot remain at rest under the action of shear force.

Question 628

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

Answer 628

σ

Question 629

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

Answer 629

2Δp

Question 630

Fluid flow in a/an __________ is an example of pressure flow.

Answer 630

pipe

Question 631

In the laminar boundary layer flow over a flat plate, the ratio (δ/x) varies as :(where, ‘δ’ is the boundary layer thickness and ‘x’ is the distance from the leading edge in the direction of flow).

Answer 631

Re^-1/2

Question 632

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

Answer 632

269

Question 633

A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m^3 ) is to be fluidised by water (density 1000 kg/m^3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is

Answer 633

4.4 KPa

Question 634

Select the wrong statement pertaining to flow of an incompressible fluid through a venturimeter.

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

Answer 634

Venturimeter occupies less space than an orificemeter.

Question 635

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

Answer 635

increase

Question 636

The bulk modulus of elasticity of a liquid

Answer 636

increases with pressure.

Question 637

Curve III in the above diagram represents a/an

Answer 637

pseudo plastic fluid

Question 638

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

Answer 638

2

Question 639

The line traced by a single fluid particle as it moves over a period of time is called __________ line.

Answer 639

path

Question 640

A stream tube is that, which has __________ cross-section entirely bounded by stream lines.

Answer 640

any convenient

Question 641

The unit of velocity head is

Answer 641

ft-lbf/lb

Question 642

Which of the following properties of a fluid is responsible for offering resistance to shear ?

a. Surface tension.
b. Viscosity.
c. Specific gravity.
d. All (a), (b), and (c).

Answer 642

Viscosity.

Question 643

Erosion and pits formation on the impeller of a centrifugal pump may be due to

Answer 643

cavitation.

Question 644

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

Answer 644

parabola

Question 645

The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the

Answer 645

net positive suction head (NPSH).

Question 646

Piezometric head is the sum of the __________ heads.

Answer 646

elevation & pressure

Question 647

Propellers are

Answer 647

axial flow mixers.

Question 648

Which of the following is not an advantage of fluidisation from transfer operation point of view?

a. Intimate contact of the fluid with all parts of the solid particles.
b. Lower fluid pumping power requirement.
c. Minimisation of temperature variation.
d. Prevention of particle seggregation.

Answer 648

Lower fluid pumping power requirement.

Question 649

Upto what value of ‘Mach number’, a fluid may be considered as incompressible ?

Answer 649

0.3

Question 650

The head developed by a centrifugal pump is largely determined by the

Answer 650

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

Question 651

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

Answer 651

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

Question 652

Flow rate of high velocity flue gas discharged through a stack to the atmosphere can be most conveniently measured by a

Answer 652

pitot tube

Question 653

Potential flow is the flow of

Answer 653

incompressible fluids with no shear.

Question 654

The value of critical Reynolds number for pipe flow is

Answer 654

1300

Question 655

Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate.

Answer 655

elastic

Question 656

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

Answer 656

fB/4

Question 657

In case of coutte flow, the fluid flow is between two large flat parallel plates with

Answer 657

top plate moving and the bottom plate fixed.

Question 658

In a stabilised soap bubble, pressure inside it compared to external pressure is

Answer 658

more

Question 659

The component of acceleration resulting due to unsteady nature of flow is called __________ acceleration.

Answer 659

local

Question 660

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

Answer 660

none of these.

Question 661

Multistage compressors are used in industry, because they

Answer 661

resemble closely to isothermal compression.

Question 662

The hydrodynamic and thermal boundary layers will merge, when

Answer 662

Prandtl number is one.

Question 663

Differential manometer measures the

Answer 663

pressure difference between two points.

Question 664

For a stable equilibrium of a submerged body (where, G and B are centres of gravity & buoyancy respectively).

Answer 664

B is above G

Question 665

With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss

Answer 665

remains constant

Question 666

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

Answer 666

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

Question 667

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

Answer 667

H^2

Question 668

The Mach number for hypersonic flow of compressible fluid is

Answer 668

> 4

Question 669

Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.)

Answer 669

d^4/5

Question 670

The valve used for very remote and accurate control of fluid is a __________ valve.

Answer 670

needle

Question 671

f = 16/NRe, is valid for

a. turbulent flow
b. laminar flow through an open channel
c. steady flow
d. none of these

Answer 671

none of these

Question 672

A mixed flow centrifugal pump

Answer 672

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

Question 673

In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature.

Answer 673

higher than

Question 674

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

Answer 674

48y

Question 675

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, the minimum fluidisation velocity, VOM is

Answer 675

16 mm/s

Question 676

One dimensional flow implies

Answer 676

a flow which does not account for changes in transverse direction.

Question 677

In case of turbulent flow of a Newtonion fluid in a straight pipe, the maximum velocity is equal to (where, Vavg = average fluid velocity)

Answer 677

1.2 Vavg

Question 678

Centrifugal compressors compared to reciprocating compressors
a. require less space.
b. have quieter operation.
c. have lower operating costs.
d. all (a), (b) and (c).

Answer 678

all of these

Question 679

For laminar flow of Newtonion fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to(where, μ = fluid viscosity )

Answer 679

1/μ

Question 680

Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the

Answer 680

bed height

Question 681

Stoke’s law is valid, when the particle Reynolds number is

Answer 681

< 1

Question 682

Which of the following is not a dimension-less parameter ?
a. Pressure-co-efficient
b. Froude number
c. Kinematic viscosity
d. Weber number

Answer 682

Kinematic viscosity

Question 683

In which of the following cases, it is possible for flow to occur from low pressure to high pressure ?
a. Flow of liquid upward in a vertical pipe.
b. Flow through a converging section.
c. Flow of air downward in a pipe.
d. Impossible in a constant cross-section conduit.

Answer 683

Flow through a converging section.

Question 684

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades.

Answer 684

outlet tip of a blade is towards the direction

Question 685

For the same terminal conditions and fitting size, the least friction loss is incurred in a/an

Answer 685

union

Question 686

A floating/submerged body is always stable, if its centre of gravity

Answer 686

lies below its centre of buoyancy.

Question 687

Critical velocity in a pipe flow

Answer 687

increases as pipe diameter increases.

Question 688

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump

a. develops a lower head.
b. capacity is reduced.
c. requires more power.
d. all (a), (b) and (c).

Answer 688

all of these

Question 689

In an incompressible flow of fluid, the fluid

Answer 689

density does not change with pressure & temperature.

Question 690

The ratio of maximum to average velocity in case of streamline flow between parallel plates is

Answer 690

1.5

Question 691

A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of __________ shape.

Answer 691

circular

Question 692

Pressure co-efficient is the ratio of pressure forces to __________ forces.

Answer 692

inertial

Question 693

Which of the following conditions must be satisfied for lift force to be developed ?
a. The body should be bluff body.
b. The body should be stream lined.
c. Circulation around the body is essentially required.
d. The main stream velocity must approach the velocity of sound in that fluid medium.

Answer 693

Circulation around the body is essentially required.

Question 694

The Reynolds number for an ideal fluid flow is

Answer 694

∞

Question 695

In case of a rotameter, the density of the float material is __________ that of the liquid it replaces.

Answer 695

more than

Question 696

The most important factor, which determines the maximum height to which water can be lifted by a pump at standard temperature is the

Answer 696

barometric pressure

Question 697

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

Answer 697

more

Question 698

What is the maximum theoretical suction lift (metres) of a reciprocating pump ?

Answer 698

10

Question 699

For an ideal fluid flow, Reynolds number is

Answer 699

∞

Question 700

The exit cone angle in case of a standard venturimeter is __________ the entrance cone angle.

Answer 700

smaller than

Question 701

A fluid is the one, which

Answer 701

cannot remain at rest under the action of shear force.

Question 702

A fluid is the one, which

Answer 702

cannot remain at rest under the action of shear force.

Question 703

One horsepower is equal to

Answer 703

550 lbf.ft/second

Question 704

The pressure head on sudden contraction in a horizontal pipe is converted into the __________ head.

Answer 704

velocity

Question 705

The pressure head on sudden contraction in a horizontal pipe is converted into the __________ head.

Answer 705

velocity

Question 706

The continuity equation of fluid mechanics utilises the principle of conservation of

Answer 706

mass