Fluid Mechanics Part 1 Flashcards

1
Q

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

A

surface tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

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

A

2100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

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

A

jet pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

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

A

as (velocity)^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

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

A

sleevejoint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

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

A

1000 P’/S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

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

A

suction minus vapor pressure of the liquid at suction temperature.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

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

A

monotonically decreases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

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

A

logarithmic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

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

A

friction co-efficient for flows at equal Reynold number.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

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

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

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

A

centrifugal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

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

A

Mach number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

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

A

smaller than

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

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

A

inverse of the fluid viscosity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

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

A

increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

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

A

directional control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

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

A

inertial forces control and viscous forces are unimportant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

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

A

more than

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

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

A

0.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

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

A

7 to 15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The dimension of dynamic viscosity is
ML^-1T^-1
L2T^-1
LT^-2
ML^-1T^-2

A

ML^-1T^-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

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

A

one fourth as that of A.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The pitot static tube does not measure the __________ pressure.
static
total
difference in static & dynamic
all of these

A

all of these

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a __________ fluid. Bingham Newtonion perfect none of these
Newtonion
26
The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is 0.5 1 1.5 2
2 ## Footnote Remember: ratio trapezoidal 2
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). 24000 24 0.24 0.44
0.44
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) Vs/Dp^2 Vs^2/Dp^2 Vs^2/Dp^3 Vs/Dp^3
Vs/Dp^2
29
The maximum delivery pressure of compressors can be upto __________ atmospheres. 10 100 250 1000
1000
30
Dimension of surface tension is(where, F = force, L = length) FL^-1 F^-1 . L F.L^-2 F^-2 . L
FL^-1
31
Which of the following is not a dimension-less parameter ? Euler number Specific gravity Fanning friction factor None of these
None of these
32
Co-efficient of velocity is __________ the coefficient of discharge. less than more than equal to not related to
more than
33
All pipes of a particular nominal size have the same inside diameter outside diameter thickness none of these
outside diameter
34
For the transfer of solution of thick slurry, the pump used is a __________ pump. reciprocating gear diaphragm centrifugal
diaphragm
35
Which of the following is not concerned with the fluid-particle interaction ? Drag co-efficient Froude number Galileo number Weber number
Weber number
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. 40 34 8 37
8 ## Footnote Remember: 15 34 90 8
37
Pressure drag does not depend upon the roughness of surface of the body. pressure of main flow only. length of the body in flow direction. all of these
all of these
38
Dimension of absolute viscosity is ML^-1T^-1 MLT^-1 ML^-1T MLT
ML^-1T^-1
39
__________ pumps are axial flow pumps. Turbine Propeller Diffuser none of these
Propeller
40
Brownian movement is prominent in the particle size range of __________ microns in case of settling of a particle in a fluid. 2 to 3 0.01 to 0.10 200 to 300 100 to 1000
2 to 3 ## Footnote Remember: Brownian 2 to 3
41
For a particle settling in water at its terminal settling velocity, which of the following is true ? Buoyancy = weight + drag Weight = buoyancy + drag Drag = buoyancy + weight Drag = weight
Weight = buoyancy + drag
42
A Bingham fluid of viscosity u = 10 Pa.s and yield stress, T0 = 10 KPa, is shared between flat parallel plates separated by a distance of 10-3 m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is 10 KPa 20 KPa 30 KPa 40 KPa
20 KPa
43
Pick out the correct statement. A forced vortex occurs when fluid rotates as a solid about an axis. In laminar flow, Newton's law of viscosity does not apply. A free vortex occurs, when fluidrotates as a solid. In turbulent flow, there are neither cross-currents nor eddies.
A forced vortex occurs when fluid rotates as a solid about an axis.
44
Shear stress in a fluid flowing in a round pipe varies parabolically across the cross-section. remains constant over the cross-section. is zero at the centre and varies linearly with the radius. is zero at the wall and increases linearly to the centre.
is zero at the centre and varies linearly with the radius.
45
The resistance wire used in a hot wire anemometer for conducting electrical current is made of copper tungsten chromium aluminium
tungsten ## Footnote Remember: resistance anemometer tungsten
46
Two dimensional stream function relates velocity and pressure. is constant along a stream line. is constant along an equipotential surface. none of these.
is constant along a stream line.
47
What causes cavitation in centrifugal pump ? High suction pressure Low barometric pressure Low suction pressure High suction velocity
Low suction pressure
48
Draining of shallow pits or sump is done by a sump pump, which is a __________ pump. single stage vertical centrifugal plunger diffuser
single stage vertical ## Footnote Remember: sump single stage vertical
49
A hydraulic ram acts as a/an __________ pump. centrifugal reciprocating impulse parallel cylinder
impulse ## Footnote Remember: hydraulic ram impulse
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 0.5 1 2 0.66
0.5
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). FL^-2T, ML^-1T^-1 FLT, ML^-1T^-1 ML^-1T^-3, F^-1L^2T F^-1L^2T^-1, MLT^-3
FL^-2T, ML^-1T^-1
52
The line of action of the buoyant force passes through the centre of gravity of the submerged body. displaced volume of the fluid. volume of fluid vertically above the body. horizontal projection of the body.
displaced volume of the fluid.
53
Pick out the wrong statement. The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonion fluids is (1) In the equation, (1) the value of 'n' for pseudoplastic and dilatant fluids are < 1 and >1 respectively. Shear stress for Newtonion fluid is proportional to the rate of shear in the direction perpendicular to motion. With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids.
With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids. ## Footnote Remember: wrong statement Mach number >0.6
54
The friction factor for turbulent flow in a hydraulically smooth pipe depends only on Reynolds number. does not depend on Reynolds number. depends on the roughness. none of these.
depends only on Reynolds number.
55
The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and moving static cold hot
moving
56
What causes convective acceleration in fluid flow ? Steep slope in flow Unsteady nature of flow Non-uniformity of flow Turbulence in flow
Non-uniformity of flow
57
The Stoke's stream function applies to the irrotational flow only. ideal/non-viscous fluids only. cases of axial symmetry. none of these.
cases of axial symmetry. ## Footnote Remember: Stoke's axial
58
Slugging in a fluidised bed can be avoided by using tall narrow vessel. deep bed of solids. shallow beds of solids and proper choice of particle size. very large particles.
shallow beds of solids and proper choice of particle size.
59
The ratio of width to depth for the most economical rectangular section in open channel flow is 0.5 1 1.5 2
2
60
The simple pitot tube measures the __________ pressure. static dynamic total none of these
total
61
Capacity of a hydraulic accumulator is defined in terms of maximum amount of energy stored. flow rate through accumulator. rate of falling of ram. volume available in the cylinder.
amount of energy stored.
62
Three piping networks as shown in the figure are placed horizontally. They are made using identical pipe segments and are subjected to the same pressure drop across them. Assuming no pressure losses at junctions, the flow rates across the three networks are related as Q1 : Q2 : Q3. https://www.indiabix.com/_files/images/chemical-engineering/fluid-mechanics/61-788-1.png 1:√3:2 1:2:3 1:2:2 1:√2:√2
1:2:2
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. Re < < 1, accelerating flow Re > > 1, accelerating flow Re < < 1, decelerating flow Re > > 1, decelerating flow
Re > > 1, decelerating flow
64
Manometers measure the __________ pressure. vacuum as well as the atmospheric difference in absolute gage
difference in
65
Which of the following fluid forces are not considered in the Navier-Stoke's equation? Gravity forces Viscous forces Pressure forces Turbulent forces
Turbulent forces
66
Which of the following may be termed as a variable orifice flowmeter ? Rotameter Pitot tube V-notch all of these
Rotameter
67
In turbulent flow, a rough pipe has the same friction factor as a smooth pipe in the zone of complete turbulence. when the roughness projections are much smaller than the thickness of the laminar film. everywhere in the transition zone. when the friction factor is independent of the Reynold's number.
when the roughness projections are much smaller than the thickness of the laminar film.
68
Air vessel provided in a reciprocating pump smoothens the flow by avoiding pulsations. increases the volumetric efficiency of the pump. saves the pump from the danger of cavitation. none of these.
none of these.
69
Bernoulli's equation is dependent on the first law of thermodynamics. third law of thermodynamics. law of conservation of momentum. none of these.
none of these. ## Footnote Remember: Bernoulli dependent none
70
The capacity of an accumulator is the maximum energy which it can store. discharge which it can deliver. liquid which it can store. none of these.
energy which it can store.
71
With increase in the temperature, viscosity of a liquid increases decreases remains constant may increase or decrease; depends on the liquid
decreases
72
Vena-contracta pressure tapping is at a distance __________ from the position of an orificemeter fitted in a pipe of internal diameter 'd' d 0.5 d 2d 4d
0.5 d ## Footnote Remembers: Vena-contracta 0.5d
73
The pump impeller and the turbine runner in a hydraulic torque converter have the same diameter. have different diameters. are directly coupled. none of these.
have different diameters.
74
Reciprocating pumps compared to centrifugal pumps deliver liquid at uniform pressure. can handle slurries more efficiently. are not subject to air binding. can be operated with delivery valve closed.
are not subject to air binding.
75
The fluid property which matters for fall-ing rain drops to acquire spherical shape is its pressure height of descend viscosity surface tension
surface tension
76
The simple pitot tube does not measure the static pressure. dynamic pressure. velocity at the stagnation point. all of these
all of these
77
Boundary layer separation occurs when the pressure reaches a minimum. cross-section of the channel is reduced. valve is closed in a pipeline. velocity of sound is reached.
cross-section of the channel is reduced.
78
The head loss in turbulent flow in a pipe varies directly as the velocity. inversely as the square of the velocity. approximately as the square of the velocity. inversely as the square of the diameter.
approximately as the square of the velocity.
79
For flow through an orifice from a reservoir, the actual velocity at the vena con-tracta is given by √2gh C.V. √2gh Cd √2gh Cc √2gh
C.V. √2gh
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 0.3 0.9 0.03 0.66
0.3
81
For the free settling of a spherical particle through a fluid, the slope of, CD-log NRe , plot is 1 -1 0.5 -0.5
-1
82
A centrifugal pump loses prime after starting. The reason of this trouble may be incomplete priming. too high a suction lift. low available NPSH and air leaks in the suction pipe. all of these
all of these
83
Venturimeter and orificemeter measures the __________ of the fluid. pressure maximum velocity average velocity point velocity
average velocity
84
Surge tanks are provided in high pressure water pipelines to store a definte quantity ofwater all the time, reduce the water hammer. facilitate easy dismantling of pipeline for cleaning and maintenance. none of these.
reduce the water hammer.
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. small differential atmospheric absolute gage
small differential
86
Isotropic turbulence occurs where there is no velocity gradient. at higher temperatures. only in Newtonion fluids. none of these.
where there is no velocity gradient. ## Footnote Remember: isotropic no velocity gradient
87
The co-efficient of drag and lift for an incompressible fluid depends on the Reynolds number Froude number Mach number all of these
Reynolds number
88
Euler's equation of motion states, that at every point, the fluid momentum is constant. force per unit mass equals acceleration. rate of mass outflow is equal to the rate of mass inflow. none of these.
force per unit mass equals acceleration.
89
Hydraulic intensifier is used for increasing the rate of velocity of liquid supply. rate of flow through delivery pipeline of a pump. intensity of pressure of the liquid. momentum rate through delivery pipe.
intensity of pressure of the liquid.
90
Which of the following is the 'Blaussius equation', relating friction factor to the Reynolds number ? f = 0.079.Nre^-0.25 f^-0.5 = 4.07 loge (NRe sqrt-f)^-0.6 none of these
f = 0.079.Nre^-0.25
91
Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of powder & grannular solids liquids low melting point semi-solids all of these
all of these
92
Euler's equation of motion is a statement expressing conservation of mass. conservation of energy. Newton's first law of motion. Newton's second law of motion.
conservation of mass.
93
During ageing of fluid carrying pipes, the pipe becomes smoother with use. friction factor increases linearly with time. absolute roughness decreases with time. absolute roughness increases linearly with time.
absolute roughness increases linearly with time.
94
Pick out the wrong statement. The form drag is dependent upon the occurrence of a wake. The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance. An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity. Existence of the boundary layer in fluid flow is because of viscosity of the fluid.
An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity.
95
Mass velocity is independent of temperature & pressure, when the flow is unsteady through unchanged cross-section. steady through changing cross-section. steady and the cross-section is unchanged. unsteady and the cross-section is changed.
steady and the cross-section is unchanged.
96
Very small pressure difference (< 5 mm water coloumn) can be most conveniently measured by a/an __________ manometer. U-tube water. U-tube mercury. inclined tube mercury. inclined tube water.
inclined tube water.
97
For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter). 1/D 1/D^2 1/D^5 D^2
1/D^5
98
The energy equation, E + P/rho + (V^2)/2g + gZ = constant (E = internal energy/mass), is applicable to perfect gases only. isothermal flow of gases. adiabatic unsteady flow of gases. all compressible fluids.
all compressible fluids.
99
A differential pressure cell is used for measuring small pressure difference in gases. measuring small pressure difference in liquids. remote recording of pressure difference. measuring the difference of the impact & the static pressure.
remote recording of pressure difference.
100
If more than two branches of pipes are to be connected at the same point, then use a/an elbow union tee none of these.
tee ## Footnote Remember: tee more than two branches
101
In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. manometric mechanical volumetric overall
manometric
102
Acceleration head in a reciprocating pump increases the work done during delivery stroke. decreases the work done during suction stroke. does not change the work requirement of the pump. increases the work done during suction stroke.
does not change the work requirement of the pump.
103
The ratio of inertial forces to elastic forces is called the __________ number. Reynolds Mach Euler Weber
Mach ## Footnote ME Mach - inertial to Elastic WS Weber - inertial to Surface tension FG Froude - inertial to Gravitational RV Reynold - inertial to Viscous EP Euler - Pressure to inertial
104
Fluid flow at increasing rate through a diverging pipe is an example of __________ flow. steady uniform non-steady uniform steady non-uniform non-steady non-uniform
non-steady non-uniform
105
The temperature in isentropic flow does not depend on Mach number. depends on Mach number only. cannot drop and then increase again downstream. none of these.
depends on Mach number only.
106
A fluid element has a velocity V = -y^2 . xi + 2yx^2 . j. The motion at (x, y) = (l/sqrt-2, 1) is rotational and incompressible rotational and compressible irrotational and compressible irrotational and incompressible
rotational and compressible
107
Check in a centrifugal pump is provided in the discharge line. generally a globe valve. provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running. all of these
all of these
108
Drag force acting on a body does not depend upon the density of the fluid. density of the body. velocity of the body. projected area of the body.
density of the body.
109
Centrifugal pump is normally classified on the basis of the rpm. type of casing. impeller blade angle. number of blades in impeller.
type of casing.
110
Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter 'd'? At the centre At d/4 from the wall At the wall At d/8 from the wall
At the wall
111
In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where, T = absolute temperature ) 1/√T 1/T √T T
√T
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 Q/2 Q/4 Q/8 Q/16
Q/16
113
Cd, Cc and Cv are related (for flow through an orifice) as (where, Cd = discharge co-efficient Cc = co-efficient of contraction (1) Cv = co-efficient of velocity (2) Cd = Cc/Cv Cd = Cc.Cv Cd = Cv/cc none of these
Cd = Cc.Cv
114
In an incompressible fluid, the density is greatly affected by moderate changes in pressure. greatly affected only by moderate changes in temperature. not affected with moderate change in temperature & pressure. sensible to changes in both temperature & pressure.
not affected with moderate change in temperature & pressure.
115
Check valves are used at high pressure. in bends. for controlling water flow. for unidirectional flow.
for unidirectional flow.
116
Velocity distribution for flow between two fixed parallel plates varies parabolically across the section. is constant over the entire cross-section. is zero at the plates and increases linearly to the midplane. none of these.
varies parabolically across the section.
117
Priming is needed in a __________ pump. reciprocating gear centrifugal diaphragm
centrifugal
118
Which of the fluid forces are not considered in the Reynold's equation of flow ? Viscous forces Turbulent forces Pressure forces Compressibility forces
Compressibility forces
119
For ideally incompressible fluid, the Mach number will be 1.5 1 0 5
1
120
A mono pump is a __________ pump. centrifugal piston positive acting rotary a group of vacuum
positive acting rotary
121
Higher specific speed (200-500) of a centrifugal pump indicates that the pump is of __________ flow type. axial radial mixed none of these
axial
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. P, Q and R P and R R and S P, Rand S
P, Q and R
123
Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller. radius of speed of fluid velocity leaving none of these
none of these
124
In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where M = molecular weight of the gas) 1/√M √M 1/M M
1/√M
125
Boundary layer separation is caused by the reduction of pressure to vapour pressure. boundary layer thickness reducing to zero. adverse pressure gradient. reduction of pressure gradient to zero.
adverse pressure gradient.
126
With increase in temperature, the vapor pressure of liquids increases increases linearly decreases remains constant
increases
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. 17 42 84 1.8
17
128
The ratio of wall drag to total drag in the Stoke's law range is 0.5 1 1/3 2/3
2/3
129
Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg. 1 0.1 0.01 0.001
0.01
130
A pitched-blade turbine draws __________ a straight blade turbine. less power than more power than same power as data insufficient to predict
less power than
131
The most suitable flow measuring device for the fluid flow measurement in a very large diameter pipeline is a weir pitot tube Kennison nozzle V-notch
pitot tube
132
A centrifugal pump is called a turbine pump, if it is having a turbine type impeller. vaned diffusion casing. rotating vaned volute. none of these.
vaned diffusion casing.
133
Remote control valve is a __________ valve. gate butterfly needle globe
butterfly
134
Which of the following quantities are computed by using the hydraulic radius for non-circular ducts ? Velocity and relative roughness. Head loss and velocity. Reynold number, relative roughness and head loss. Reynolds number and friction factor.
Reynold number, relative roughness and head loss.
135
Centre of pressure in an immersed body is __________ the centre of gravity. above below at either above or below; depends on the liquid density
below
136
The centre of pressure is always below the centroid of the area. always above the centroid of the area. a point on the line of action of the resultant force. at the centroid of the submerged area.
a point on the line of action of the resultant force.
137
Pascal law is not applicable for a/an __________ fluid. accelerating frictionless static uniformly moving none of these
none of these
138
In a fluidised bed reactor temperature gradients are very high. temperature is more or less uniform. hot spots are formed. segregation of the solids occurs.
temperature is more or less uniform.
139
The flow of a liquid through tapering pipe at a constant rate is an example of __________ flow. steady uniform steady non uniform unsteady uniform unsteady non uniform
steady non uniform
140
Pick out the correct statement pertaining to transition/ entrance length in fluid flow. The length of entrance region of pipe, in which full development of fluid flow takes place such that velocity profile does not change downstream, is called the transition length. Transition length for laminar flow of Newtonion fluids in a pipe of diameter 'd' is equal to 0.05. D.NRe. Transition length for turbulent flow of Newtonion fluids in a smooth pipe of diameter 'd' is equal to 50 D. all of these
all of these
141
A perfect gas does not satisfy PV = nRT. is incompressible and has zero viscosity. has constant specific heat. can't develop shear stresses.
has constant specific heat.
142
In a/an __________ , the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure. rotameter pitot tube venturimeter flow nozzle
pitot tube
143
During fluid flow, variation of shear stress(T) with velocity gradientat (dv/dy) constant pressure temperature is shown below in the figure. https://www.indiabix.com/_files/images/chemical-engineering/fluid-mechanics/49-680-2.png In the above figure, Binghom plastic is represented by the curve . V II III I
II
144
Speed of sound in an ideal gas depends on its temperature pressure specific volume none of these
temperature
145
A centrifugal pump designed for handling water (u = 1 cp) will deliver __________ when pumping a thicker oil (u = 30 cp). less head & capacity more head more capacity less head & more capacity
less head & capacity
146
If 'x' is the depth of flow in an open channel of large width, then the hydraulic radius is equal to x x/2 x/3 2x/3
x
147
In fluid flow, the boundary layer separation can not occur in case of boundaries experiencing form drag. at points of abrupt changes in the flow directions. in laminar flow. none of these.
none of these.
148
For a given fluid flow rate, which of the following incurs maximum head loss ? Orifice meter Venturimeter Flow nozzle All of them incur the same head loss
Orifice meter
149
Which of the following assumptions enables the Euler's equation of motion to be integrated ? The fluid is incompressible. The fluid is non-viscous. The continuity equation is satisfied. The flow is rotational and incompressible.
The fluid is incompressible.
150
A fluid whose apparent viscosity increases with shear rate is termed as the __________ fluid. Newtonion viscous dilatant non-viscous
dilatant
151
Which of the following is the most common pump for pumping either raw sewage or sludge ? Electromagnetic pump Centrifugal pump Reciprocating pump Gear pump
Reciprocating pump
152
Transition length for a turbulent fluid entering into a pipe is around __________ times the pipe diameter. 5 50 500 1000
50
153
For turbulent flow of an incompressible fluid through a pipe, the flow rate Q is proportional to (delta- P)n, where delta-P is the pressure drop. The value of exponent 'n' is 1 0 < 1 > 1
< 1
154
Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have very low speeds. smaller discharge. higher capital &maintenance cost. high vibrations.
higher capital &maintenance cost.
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) D = 1840 H^0.5/N D = 1840 N/H^0.5 H = 1840 D^0.5/N D = 1840 H/N
D = 1840 H^0.5/N
156
Which of the following pipe bends will incur the largest head loss ? U-bend 30 bend 45 bend 90 bend
U-bend
157
Which is the most efficient and best for measuring very small flow rate of gases ? Venturimeter Orifice meter Rotameter Flow nozzle
Rotameter
158
When the water is warm, the height to which it can be lifted by a pump decreases due to reduced viscosity. decreases due to reduced vapour pressure. increases due to increased vapour pressure decreases due to increased frictional resistance.
decreases due to reduced vapour pressure.
159
Pipes having diameter 14 inches or more are designated by their outside diameter inside diameter schedule number none of these
outside diameter
160
Viscosity of water at 40 C lies in the range of 1 x 10^-3 to 2 x 10^-3 kg/m.s 0.5 x 10^-3 to 1 x 10^-3 kg/m.s 1 to 2 kg/m.s 0.5 to 1 kg/m.s
0.5 x 10^-3 to 1 x 10^-3 kg/m.s
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. 500 200 1000 750
500
162
The dimension of kinematic viscosity is ML^-2T^-1 L^2T^-1 ML^-2T^-2 none of these
L^2T^-1
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 20 m/sec 10 m/sec 5sqrt-2 m/sec 5 m/sec
10 m/sec
164
Turbulent flow generally occurs for cases involving highly viscous fluid very narrow passages very slow motion none of these
none of these
165
Lower BWG means __________ of the tube. lower thickness lower cross-section outer diameter inner diameter
lower cross-section
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. logarithmic parabolic hyperbolic linear
parabolic
167
The Prandtl mixing length is zero at the pipe wall and is a universal constant. independent of radial distance from the pipe axis. independent of the shear stress. useful for computing laminar flow problems.
useful for computing laminar flow problems.
168
N^2Re/NFr is called the __________ number. Brinkman Galileo Archimedes Euler
Galileo
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) 2y/3 3y/4
2y/3
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 << 1 increases linearly with V. decreases linearly with V. decreases as V^2. none of these.
increases linearly with V.
171
Self-priming centrifugal pump can be used for booster service. pumping liquid fertilisers (e.g. liquid NH3). pumping industrial wastes. all of these
all of these
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 pipe length fluid velocity in the pipe time taken to close the valve all of these
all of these
173
Bernoull's equation does not apply to the functioning of a/an venturimeter orificem pitot tube none of these
none of these
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 'delta-p' with average velocity 'Vavg'? D delta-p/8L D delta-p/4L 8 . Vavg/D 4 . Vavg/D
8 . Vavg/D
175
Pascal's law is valid, only when the fluid is frictionless and at rest. at rest. at rest and when the frictionless fluid is in motion. none of these.
at rest.
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. 10 m 11 m 12 m 20 m
11 m
177
The pressure head of a flow meter remains constant for venturimeter orificemeter rotameter pitot tube
rotameter
178
A venturimeter can not be used for the direct measurement of datum difference in the stretch of pipeflow pressure difference in the flow throughpipeline. friction loss in pipe flow. all of these
all of these
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 head discharge efficiency none of these
discharge
180
Which of the following is used for very accurate measurement of flow of gas at low velocity ? Pitot tube Rotameter Segmental orificemeter Hot wire annemometer
Hot wire annemometer