Fluid Mechanics Flashcards
The fluid property, due to which, mercury does not wet the glass is
surface tension
viscosity
cohesion
adhesion
surface tension
Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds
4000
2100
1500
3000
2100
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
jet pump
The normal stress is the same in all directions at a point in a fluid, when the fluid is
non-viscous.
incompressible.
both (a) and (b).
having no motion of one fluid layer relative to the other.
having no motion of one fluid layer relative to the other.
Head developed by a centrifugal pump depends on its
speed
impeller diameter
both (a) and (b)
neither (a) nor (b)
both (a) and (b)
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
flow rate
mean velocity
both ‘a’ & ‘b’
neither ‘a’ nor ‘b’
mean velocity
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
as (velocity)²
Most commonly used joint in the underground pipe lines is the
sleevejoint
coupling
flange
expansion joint
sleevejoint
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
1000 P’/S
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.
suction minus vapor pressure of the liquid at suction temperature.
With increasing flow rate, the hydraulic efficiency of a centrifugal pump
monotonically decreases.
decreases and then increases.
remains constant.
increases and then decreases.
monotonically decreases.
The velocity profile for turbulent flow through a closed conduit is
logarithmic
parabolic
hyperbolic
linear
logarithmic
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 (a), (b) & (c).
friction co-efficient for flows at equal Reynold number.
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.
rapid pressure change due to a rapid change in the rate of flow.
Molten soap mass is transported by a __________ pump.
diaphragm
reciprocating
gear
centrifugal
centrifugal
Which of the following denotes the effect of compressibility in fluid flow ?
Weber number
Mach number
Euler number
Reynolds number
Mach number
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
smaller than
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.
inverse of the fluid viscosity.
If the discharge of a centrifugal pump is throttled, then its suction lift
increases
decreases
remains unchanged
data insufficient to predict
increases
Foot valves provided in pumps are __________ valves.
relief
three/four way
pressure reducing
directional control
directional control
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.
inertial forces control and viscous forces are unimportant.
Power loss in an orificemeter is __________ that in a venturimeter.
less than
same as
more than
data insufficient, cannot be predicted
more than
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
0.5
What is the normal range of exit cone angle of a venturimeter ?
2 to 5
7 to 15
15 to 25
>25
7 to 15
The dimension of dynamic viscosity is
ML⁻¹T⁻¹
L²T⁻¹
LT⁻²
ML⁻¹T⁻²
ML⁻¹T⁻¹
A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke’s law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity
same as that of A.
one fourth as that of A.
twice as that of A.
four times as that of A.
one fourth as that of A.
The pitot static tube does not measure the __________ pressure.
static
total
difference in static & dynamic
all (a), (b) and (c)
all (a), (b) and (c)
The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a __________ fluid.
Bingham
Newtonion
perfect
none of these
Newtonion
In fluid flow, cavitation is caused, if the
fluid velocity decreases to zero.
total energy decreases.
both (a) and (b).
flow pressure approaches its vapor pressure at the prevailing temperature.
flow pressure approaches its vapor pressure at the prevailing temperature.
The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is
0.5
1
1.5
2
2
The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10⁻⁶m²/s).
24000
24
0.24
0.44
0.44
For Laminar flow through a packed bed, the pressure drop is proportional to (Vs is the superficial liquid velocity and Dp is the particle diameter)
Vₛ/Dp²
Vₛ²/Dp²
Vₛ²/Dp³
Vₛ/Dp³
Vₛ/Dp²
The maximum delivery pressure of compressors can be upto __________ atmospheres.
10
100
250
1000
1000
Dimension of surface tension is(where, F = force, L = length)
FL⁻¹
F⁻¹ · L
F · L⁻²
F⁻² · L
FL⁻¹
Which of the following is not a dimension-less parameter ?
Euler number
Specific gravity
Fanning friction factor
None of these
None of these
Co-efficient of velocity is __________ the coefficient of discharge.
less than
more than
equal to
not related to
more than
All pipes of a particular nominal size have the same
inside diameter
outside diameter
thickness
none of these
outside diameter
For the transfer of solution of thick slurry, the pump used is a __________ pump.
reciprocating
gear
diaphragm
centrifugal
diaphragm
Which of the following is not concerned with the fluid-particle interaction ?
Drag co-efficient
Froude number
Galileo number
Weber number
Weber number
Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be __________ ft.
40
34
8
37
8
Pick out the wrong statement.
Momentum transfer in laminar flow results from veclocity gradient.
A fluid in equilibrium is not free from shear stress.
The viscosity of a non-Newtonion fluid is a function of temperature only.
both (b) and (c)
both (b) and (c)
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 (a), (b) and (c)
all (a), (b) and (c)
Dimension of absolute viscosity is
ML⁻¹T⁻¹
MLT⁻¹
ML⁻¹T
MLT
ML⁻¹T⁻¹
__________ pumps are axial flow pumps.
Turbine
Propeller
Diffuser
none of these
Propeller
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
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
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
10 KPa
20 KPa
30 KPa
40 KPa
20 KPa
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.
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.
The resistance wire used in a hot wire anemometer for conducting electrical current is made of
copper
tungsten
chromium
aluminium
tungsten
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.
What causes cavitation in centrifugal pump ?
High suction pressure
Low barometric pressure
Low suction pressure
High suction velocity
Low suction pressure
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
A hydraulic ram acts as a/an __________ pump.
centrifugal
reciprocating
impulse
parallel cylinder
impulse
The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonion fluid in a circular pipe is
0.5
1
2
0.66
0.5
Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively).
FL⁻²T, ML⁻¹T⁻¹
FLT, ML⁻¹T⁻¹
ML⁻¹T⁻³, F⁻¹L²T
F⁻¹L²T⁻¹, MLT⁻³
FL⁻²T, ML⁻¹T⁻¹
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.
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 D/4L · Δp
In the equation, τ · g꜀ = k · (du/dy)ⁿ 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.
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.
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
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
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.
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.
The ratio of width to depth for the most economical rectangular section in open channel flow is
0.5
1
1.5
2
2
The simple pitot tube measures the __________ pressure.
static
dynamic
total
none of these
total
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.
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.
(insert image here S2P4) 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
With diminishing cross-sectional area in case of subsonic flow in a converging nozzle, the
velocity increases
pressure decreases
both (a) & (b)
neither (a) nor (b)
both (a) & (b)
Boundary layer separation is characterised by one of the conditions given below, where ‘Re’ is the Reynolds number for the flow. Select the appropriate conditions.
Re «_space;1, accelerating flow
Re»_space; 1, accelerating flow
Re «_space;1, decelerating flow
Re»_space;1, decelerating flow
Re»_space;1, decelerating flow
Manometers measure the __________ pressure.
vacuum as well as the atmospheric
difference in
absolute
gage
difference in
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
Which of the following may be termed as a variable orifice flowmeter ?
Rotameter
Pitot tube
V-notch
All (a), (b) and (c)
Rotameter
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.
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.
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.
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.
With increase in the temperature, viscosity of a liquid
increases
decreases
remains constant
may increase or decrease; depends on the liquid
decreases
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
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.
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.
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
The simple pitot tube does not measure the
static pressure.
dynamic pressure.
velocity at the stagnation point.
all (a), (b) and (c).
all (a), (b) and (c).
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.
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.
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)
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
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
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 (a), (b), and (c).
all (a), (b), and (c).
Venturimeter and orificemeter measures the __________ of the fluid.
pressure
maximum velocity
average velocity
point velocity
average velocity
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.
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
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.
The co-efficient of drag and lift for an incompressible fluid depends on the
Reynolds number
Froude number
Mach number
all (a), (b) and (c)
Reynolds number
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.
The Navier-Stokes equation deals with the law of conservation of
mass
energy
both (a) & (b)
momentum
momentum
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.
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√f)^0.6
f^-0.5 = -4 logₑ [(εD/3.70) + (1.26/NRe ·√f]
none of these
f = 0.079·(NRe)^-0.25
Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of
powder & grannular solids
liquids
low melting point semi-solids
all ‘a’, ‘b’ & ‘c’
all ‘a’, ‘b’ & ‘c’
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.
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.
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.
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.
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.
For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter).
1/D
1/D²
1/D⁵
D²
1/D⁵
For a given Reynold number as d/D for an orifice increases, Cd will (where, d & D are orifice & pipe diameters respectively).
increase
decrease
remain constant
either (a) or (b); depends on other factors
increase
The energy equation, E + (P/ρ) + (v²/2g) + 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.
What is the ratio of fluid carrying capacity of two pipes having diameters d1 and d2 respectively ?
(d1/d2) ^0.8
(d1/d2)^0.5
(d1/d2)
(d1/d2)^2
(d1/d2)^0.5
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.
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
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
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.
The ratio of inertial forces to elastic forces is called the __________ number.
Reynolds
Mach
Euler
Weber
Mach
The equivalent diameter for flow through a rectangular duct of width B and height H is
HB/[2(H+B)]
HB/(H+B)
2HB/(H+B)
4HB/(H+B)
2HB/(H+B)
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
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.
A fluid element has a velocity V = -y2 . xi + 2yx2 . j. The motion at (x, y) = (l/2, 1) is
rotational and incompressible
rotational and compressible
irrotational and compressible
irrotational and incompressible
rotational and compressible
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 (a), (b) and (c).
all (a), (b) and (c).
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.
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.
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
In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where, T = absolute temperature )
1/√T
T
1/T
√T
T
√T
Applying a pressure drop across a capillary results in a volumetric flow rate ‘Q’ under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is
Q/2
Q/4
Q/8
Q/16
Q/16
Cd, Cc and Cv are related (for flow through an orifice) as (where, Cd = discharge co-efficient
Cc = co-efficient of contraction
= area of jet at vena-contracta/area of opening
Cv = co-efficient of velocity
=actual velocity at vena-contracta/theoretical velocity)
Cd = Cc/Cv
Cd = Cc · Cv
Cd = Cv/cc
none of these
Cd = Cc · Cv
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.
Check valves are used
at high pressure.
in bends.
for controlling water flow.
for unidirectional flow.
for unidirectional flow.
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.
Priming is needed in a __________ pump.
reciprocating
gear
centrifugal
diaphragm
centrifugal
An ideal nozzle design aims at
minimising wall friction.
suppressing boundary layer separation.
both (a) & (b).
neither (a) nor (b).
both (a) & (b).
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
For ideally incompressible fluid, the Mach number will be
1.5
1
0
5
1
A mono pump is a __________ pump.
centrifugal
piston
positive acting rotary
a group of vacuum
positive acting rotary
Higher specific speed (200-500) of a centrifugal pump indicates that the pump is of __________ flow type.
axial
radial
mixed
none of these
axial
The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost are
P. Inlet pressure Q. Compressor rpm
R. Delivery pressure S. Volumetric flow rate at inlet.
P, Q and R
P and R
R and S
P, Rand S
P, Q and R
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
An ideal fluid is
non-viscous
incompressible
both (a) & (b)
neither (a) & (b)
both (a) & (b)
Pick out the Hagen-Poiseulle’s equation.
Δp/ρ = 4f・L/D・v²/2gc
Δp = 32・μLV/gcD²
Δp/L = 150・(1-ε)/ε³ ・μv₀²/gc²Dₚ
Δp/L = 1.75・(1-ε)/ε³ ・ρv₀²/gcDₚ
Δp = 32・μLV/gcD²
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
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.
With increase in temperature, the vapor pressure of liquids
increases
increases linearly
decreases
remains constant
increases
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
The ratio of wall drag to total drag in the Stoke’s law range is
0.5
1
1/3
2/3
2/3
Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg.
1
0.1
0.01
0.001
0.01
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
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
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.
Remote control valve is a __________ valve.
gate
butterfly
needle
globe
butterfly
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.
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
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.
The uniformity of a gas fluidised bed depends upon the __________ of the solid particles.
size
surface properties
both (a) and (b)
neither (a) nor (b)
both (a) and (b)
Pascal law is not applicable for a/an __________ fluid.
accelerating frictionless
static
uniformly moving
none of these
none of these
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.
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
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 (a), (b) and (c).
all (a), (b) and (c).
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.
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
During fluid flow, variation of shear stress(τ) with velocity gradientat constant pressure temperature is shown below in the figure
(image S4P2 - 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
Speed of sound in an ideal gas depends on its
temperature
pressure
specific volume
none of these
temperature
A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp).
less head & capacity
more head
more capacity
less head & more capacity
less head & capacity
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
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.
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
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.
In case of a pipe exit fitted with a nozzle, the
conversion of kinetic head to pressure head is facilitated.
conversion of pressure head to kinetic head is facilitated.
power transmitted through the nozzle is maximum, when the head lost due to friction in the pipe is equal to one third of the total supply head.
both (b) and (c)
both (b) and (c)
A fluid whose apparent viscosity increases with shear rate is termed as the __________ fluid.
Newtonion
viscous
dilatant
non-viscous
dilatant
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
Transition length for a turbulent fluid entering into a pipe is around __________ times the pipe diameter.
5
50
500
1000
50
For turbulent flow of an incompressible fluid through a pipe, the flow rate Q is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent ‘n’ is
1
0
< 1
> 1
0
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.
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
Which of the following pipe bends will incur the largest head loss ?
U-bend
30° bend
45° bend
90° bend
U-bend
Which is the most efficient and best for measuring very small flow rate of gases ?
Venturimeter
Orifice meter
Rotameter
Flow nozzle
Rotameter
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.
Pipes having diameter 14 inches or more are designated by their
outside diameter
inside diameter
schedule number
none of these
outside diameter
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
A centrifugal pump has the following specifications:
Power = 4 H.P.; Speed = 800 rpm
Head = 8 metres
Flow = 1000 litres/minutes.
If its speed is halved, the new discharge will be __________ litres/minute.
500
200
1000
750
500
The dimension of kinematic viscosity is
ML⁻²T⁻¹
L²T⁻¹
ML⁻²T⁻²
none of these
L²T⁻¹
A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the average velocity of water flowing through the main pipe is 5 m/sec, the average velocity through the bifurcated pipes is
20 m/sec
10 m/sec
5√2 m/sec
5 m/sec
10 m/sec
Turbulent flow generally occurs for cases involving
highly viscous fluid
very narrow passages
very slow motion
none of these
none of these
Lower BWG means __________ of the tube.
lower thickness
lower cross-section
outer diameter
inner diameter
lower cross-section
For laminar flow of Newtonion fluid in a circular pipe, the velocity distribution is a function of the distance ‘d’ measured from the centre line of the pipe, and it follows a __________ relationship.
logarithmic
parabolic
hyperbolic
linear
parabolic
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.
NRe²/NFr is called the __________ number.
Brinkman
Galileo
Archimedes
Euler
Galileo
The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which “sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis”. The centre of pressure of a rectangular surface (of width ‘w’) immersed vertically in a static mass of fluid is at a depth of(where, y = depth of the liquid)
1/(y/3)
2y/3
1/(y/4)
3y/4
2y/3
As the velocity V and thus the Reynolds number of a flow past a sphere increases from very low value, the drag force for Re «_space;1
increases linearly with V.
decreases linearly with V.
decreases as V².
none of these.
increases linearly with V.
Self-priming centrifugal pump can be used for
booster service.
pumping liquid fertilisers (e.g. liquid NH3).
pumping industrial wastes.
all (a), (b) and (c).
all (a), (b) and (c).
Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve. The extent of pressure thus produced due to water hammer depends on the
pipe length
fluid velocity in the pipe
time taken to close the valve
all (a), (b) and (c)
all (a), (b) and (c)
Bernoull’s equation does not apply to the functioning of a/an
venturimeter
orificem
pitot tube
none of these
none of these
What is the shear rate at the pipe wall, in case of laminar flow of Newtonion fluids in a pipe of diameter ‘D’ & length ‘L’ incurring a pressure drop ‘Δp’ with average velocity ‘Vavg’?
D Δp/8L
D Δp/4L
8・Vavg/D
4・Vavg/D
8・Vavg/D
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.
A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit (E) to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062.
(image S4P9 -
https://www.indiabix.com/_files/images/chemical-engineering/fluid-mechanics/61-793-1.png)
10 m
11 m
12 m
20 m
11 m
The pressure head of a flow meter remains constant for
venturimeter
orificemeter
rotameter
pitot tube
rotameter
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 (a), (b) and (c).
all (a), (b) and (c).
A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double
head
discharge
efficiency
none of these
discharge
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
The rate of shear versus the shear stress curves are time dependent for __________ fluid.
thixotropic
rheopectic
both (a) & (b)
neither (a) nor (b)
both (a) & (b)
In Newton’s law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is
0.44
0.044
4.4
44
0.44
A pressure of 10 m head of water is equivalent to __________ kN/m^2.
98
147
196
49
98
A pressure head of 320 metres of water in meters of CCl4 (sp.gr = 1.6) will be
100
200
320
160
200
Pick out the Kozney-Karman equation (valid for low NRe) for fluid flow through a packed bed of solids.
Δp/ρ = 4f・L/D・v²/2gc
fₚ= 150(1-ε) /NRe + 1.75
[Δp・gc・Dₚ²・ε³ ] / [L・v₀・μ(1-ε)²] = 150
(Δp/δ・L)・(gc/v₀²)・(Dₚ・ε³/1-ε) = 1.75
[Δp・gc・Dₚ²・ε³ ] / [L・v₀・μ(1-ε)²] = 150
The ratio of the wall drag to the form drag in the Stoke’s law range (for motion of spherical particles in a stationary fluid) is
0.5
1
2
0.33
2
For turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance ‘d’ measured from the wall of the pipe and the friction velocity ‘v’, and it follows a __________ relationship.
logarithmic
linear
hyperbolic
parabolic
logarithmic
Maintenance cost of a __________ pump for a particular duty is the least.
centrifugal
reciprocating
volute
gear
centrifugal
Choking in case of pipe flow means that a
specified mass flow rate can not be achieved.
valve is closed in the line.
restriction in flow cross-section area occurs.
none of these.
specified mass flow rate can not be achieved.
Velocity of liquid hydrocarbon fuels in a pipeline can not be measured by magnetic flowmeters, because their __________ is very low/small.
thermal conductivity
electrical conductivity
specific gravity
electrical resistivity
electrical conductivity
The nominal size of a hose pipe is specified by its
I.D.
O.D.
thickness
none of these
I.D.
Transition from laminar flow to turbulent flow is aided by the
surface roughness and curvature (i.e.sharp corners).
vibration.
pressure gradient and the compressibility of the flowing medium.
all (a), (b) & (c).
all (a), (b) & (c).
For flow of fluids through packed bed, the superficial velocity is
less than the average velocity through channels.
more than the average velocity through channels.
dependent on the pressure drop across the bed.
same as the average velocity through channels.
less than the average velocity through channels.
Cd is always __________ Cc.
greater than
less than
equal to
either more or less than
greater than
Buoyant force
for non-symmetrical bodies is not vertical.
depends on the depth of the submergence of the floating body.
depends on the weight of the floating body.
none of these.
depends on the weight of the floating body.
Which of the following is an undesirable property of a manometric liquid ?
Non-sticky & non-corrosive nature.
High vapour pressure.
Low viscosity & surface tension.
Low co-efficient of thermal expansion.
High vapour pressure.
Characteristic curves for a centrifugal pump plotted against its capacity is shown in the diagram. x, y and z denote respectively
(Image S5P3 - https://www.indiabix.com/_files/images/chemical-engineering/fluid-mechanics/45-628-1.png)
efficiency, head and B.H.P.
head, efficiency and B.H.P.
B.H.P., efficiency and head
efficiency, B.H.P. and head
head, efficiency and B.H.P.
Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head.
manometric
total
static
friction
manometric
The speed of sound in an ideal gas varies as the
temperature
pressure
density
none of these
temperature
The maximum head that can be developed by a single impeller is __________ ft.
25
100
250-300
1000
250-300
The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is
< 1
1
> 1
2
< 1
The general relationship between speed N, head H, power P and discharge Q for a centrifugal pump is
Q∝N : H∝N² : P∝N³
Q∝N² : H∝N³ : P∝N
Q∝N : H∝N³ : P∝N²
Q∝N³ : H∝N : P∝N²
Q∝N : H∝N² : P∝N³
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 ?
0.5
0.67
1
2
2
Foot valve provided in the pump is a __________ valve.
direction control
back pressure
relief
pressure reduction
back pressure
The discharge co-efficient for an orificemeter does not depend upon the
pipe length.
ratio of pipe diameter to orifice diameter.
type of orifice & the Reynolds number.
pipe diameter.
pipe length.
Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump?
Increasing the impeller speed and the volute area.
Increasing the number of vanes in the impeller.
Mounting of two or more impellers in series on a single shaft.
Either of (a), (b) or (c).
Mounting of two or more impellers in series on a single shaft.
An equipotential line is __________ to the velocity vector at every point.
normal
abnormal
tangential
none of these
normal
Specific speed for a centrifugal pump is
N√Q / (H)^3/4
N√Q / (H)^2/3
N³D⁵ / (H)^1/3
N√Q/H
N√Q / (H)^3/4
Path followed by water jet issuing from the bottom of a water tank will be a
parabola (vertex being at the opening).
hyperbola.
horizontal straight line.
zig-zag path (which is geometrically undefined).
parabola (vertex being at the opening).
Which of the following produces maximum pressure difference for transportation of gases ?
Vaccum pumps
Blowers
Fans
Compressors
Compressors
For flow through a venturi at a particular discharge, the correct relationships among velocities at point X, Y and Z would be
(image S5P6 - https://www.indiabix.com/_files/images/chemical-engineering/fluid-mechanics/11-146-1.png)
V1 < V2 < V3
V2 > V1 and V2 > V3
V1 > V2 > V3
none of these.
V2 > V1 and V2 > V3
Drag co-efficient in hindered settling is __________ that in free settling.
less than
equal to
not necessarily greater than
always greater than
always greater than
Efficiency of power transmission (η) through a circular pipe is given by (ht - hf)/ht, which has a maximum value of __________ percent.
33:3
50
66.6
88.8
66.6
One dimensional fluid flow implies the
flow in straight lines only.
uniform flow.
steady uniform flow.
flow in which transverse components are zero.
flow in which transverse components are zero.
__________ forces act on a particle moving through a stationary fluid.
Gravity
Drag
Buoyant
all (a), (b), & (c)
all (a), (b), & (c)
In frictional fluid flow, the quantity,
(P/ρ)+(v²/2gc)+gz/gc, is
constant along a streamline.
not constant along a streamline.
increased in the direction of flow.
none of these.
not constant along a streamline.
Hydraulic radius is the ratio of
wetted perimeter to flow area.
flow area to wetted perimeter.
flow area to square of wetted perimeter.
square root of flow area to wetted perimeter.
flow area to wetted perimeter.
The unit of bulk modulus of elasticity for a liquid in S.I. unit is
N
N/m
N/m²
N/m³
N/m²
Power requirement of fans having constant wheel diameter varies __________ fan speed.
as square of
directly as
as cube of
none of these
as cube of
In the low Reynolds number region, the drag force on a sphere is proportional to
V
V^2
V^4
V^0.5
V
The continuity equation
is independent of the compressibility of the fluid.
is dependent upon the viscosity of the fluid.
represents the conservation of mass.
none of these.
represents the conservation of mass.
Experimental study of laminar fluid flow through a circular tube was conducted by
Reynolds
Hagen and Poiseuille
Pascal
Blake-Plummer
Hagen and Poiseuille
The most economical flow control valve for use with large diameter pipes is a
butterfly valve
globe valve
needle valve
none of these
butterfly valve
Each term in Bernaulli’s equation represents the __________ of the fluid.
energy per unit mass
energy per unit weight
force per unit mass
none of these
energy per unit weight
Which of the following is a dimensionless parameter ?
Angular velocity
Specific weight
Kinematic viscosity
None of these
None of these
If the head over the triangular notch is doubled, the discharge will increase by __________ times.
2
2.828
5.657
4
5.657
Friction factor for a hydraulically smooth pipe at NRe = 2100 is f1. If the pipe is further smoothened (i.e., roughness is reduced), the friction factor at the same value of NRe, will
increase.
decrease.
remain unchanged.
increase or decrease depending on the pipe material.
remain unchanged.
What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water iterface? The balloon is of radius 0.1 m and is filled with air.
4πg/3
0.01πgH/4
0.01πgH/8
0.04πgH/3
4πg/3
For the laminar flow of a fluid in a circular pipe of radius R, the Hagen-Poisseule equation predicts the volumetric flow rate to be proportional to
R
R^2
R^4
R^0.5
R^4
Interstage coolers are provided in a multistage compressor to
save power in compressing a given volume to a given pressure.
cool the delivered air.
achieve the exact delivery pressure.
none of these.
save power in compressing a given volume to a given pressure.
Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases.
NPSH required.
BHP required by the pump.
head of the liquid pumped.
all (a), (b) and (c).
all (a), (b) and (c).
Reynolds number is the ratio of
viscous forces to gravity forces.
inertial forces to viscous forces.
viscous forces to inertial forces.
inertial forces to gravity forces.
inertial forces to viscous forces.
For the manometer set up shown in the figure, the pressure difference PA - PB is given by
(image S5P10) - https://www.indiabix.com/_files/images/chemical-engineering/fluid-mechanics/60-786-1.png
(ρH - ρair) gH
(ρH - ρL) gH
(ρH - ρL) gH + (ρL - ρair) . g(L - H)
(ρH - ρL) gL + (ρL - ρair) gH
(ρH - ρair) gH
The discharge through a venturimeter depends upon
pressure drop only.
its orientation.
co-efficient of contraction only.
none of these.
pressure drop only.
N. second/m² is
the S.I. unit of dynamic viscosity.
the S.I. unit of kinematic viscosity.
equivalent to one poise.
equivalent to one stoke.
the S.I. unit of dynamic viscosity.
The distance between metacentre and __________ is called metacentric height.
water surface
centre of gravity
centre of buoyancy
none of these
centre of gravity
Check valve is used for __________ flow.
very precise control of
unidirectional
multidirectional
none of these
unidirectional
Capacity of a rotary gear pump can be varied by
changing the speed of rotation.
bleeding air into suction.
bypassing liquid from the suction or discharge line.
all (a), (b) and (c).
all (a), (b) and (c).
For a given Reynolds number, in a hydraulically smooth pipe, further smoothening __________ the friction factor.
brings about no further reduction of
increases
decreases
none of these
brings about no further reduction of
Power number is the ratio of
drag stress to inertial stress.
inertial stress to drag stress.
inertial stress to gravitational stress.
gravitational stress to drag stress.
drag stress to inertial stress.
The momentum correction factor for the velocity distribution of laminar flow is
1.3
1.66
2.5
none of these
none of these
For the same flow rate of a fluid, the pressure drop is the least for
venturimeter
orificemeter
flow-nozzle
Δp is same for all
venturimeter
The valve commonly used in pipes larger than 2” dia is a
globe valve
plug-cock
gate valve
check valve
gate valve
Foot valves are provided in the suction line of a centrifugal pump to
avoid priming, every time we start the pump.
remove the contaminant present in the liquid.
minimise the fluctuation in discharge.
control the liquid discharge.
avoid priming, every time we start the pump.
An ideal fluid is
frictionless & incompressible.
one, which obeys Newton’s law of viscosity.
highly viscous.
none of these.
frictionless & incompressible.
In area meter (e.g., rotameter), with increase in the fluid flow rate, the
pressure drop increases linearly.
pressure drop is almost constant.
area through which fluid flows does not vary.
none of these.
pressure drop is almost constant.
Drag co-officient CD, in Stoke’s law range is given by
CD= 16/Re,p
CD = 24/Re,p
CD = 18.4/Re,p
CD = 0.079/(Re)^0.25,p
CD = 24/Re,p
In power law, ζ = A (du/dy)² + B , then the fluid is
Newtonian
dilatant
thixotropic
rheopectic
Newtonian
The buoyant force acting on a floating body is dependent on the
viscosity of the liquid.
weight of the liquid displaced.
depth of immersion of the body.
surface tension of the liquid.
weight of the liquid displaced.
A Newtonion fluid is that
which follows Newton’s law of motion.
which needs a minimum shear, before it starts deforming.
for which shear & deformation are related as τ = μ(∂u/∂u)
none of these.
for which shear & deformation are related as τ = μ(∂u/∂u)
In case of end to end connection of two or more pipes in series, the __________ each pipe.
same rate of flow passes through
head loss is same through
rate of flow in each pipe is proportional to the length of
total flow rate is the sum of flow rate in
same rate of flow passes through
Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?
Fanning equation
Blake-Pllummer equation
Hagen-Poiseulle equation
Kozney-Karman equation
Blake-Pllummer equation
The flow of gas along a pipe in the direction of decreasing pressure causes decrease in its
viscosity
specific volume
velocity
none of these
specific volume
Centrifugal pump can’t be used to pump
molten sodium (used as a coolant in Fast Breeder Reactor).
moderately viscous vegetable oil used in soap industry.
thick molten soap at 80°C.
none of the above.
thick molten soap at 80°C.
A stream line is
fixed in space in steady flow.
always the path of particle.
drawn normal to the velocity vector at every point.
a line connecting the mid points of flow cross-section.
fixed in space in steady flow.
Quicksand is an example of a __________ fluid.
bingham plastic
dilatent
Newtonion
pseudoplastic
dilatent
Correction for capillary effect in manometers (used for pressure measurement) need not be applied, if diameter of the manometer tube is __________ mm.
< 4
> 4
> 12.5
< 10
> 12.5
Differential manometer measures the
absolute pressure
gauge pressure
pressure difference
pressure gradient
pressure difference
The pressure and power requirement of a gas fan at constant speed & capacity varies __________ the gas density.
directly as
inversely as square root of
inversely as
as square of
directly as
Isothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the
wall roughness.
Reynolds number.
both (a) & (b).
neither (a) nor (b).
both (a) & (b).
Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.)
√d
d^1/3
d^2
d^2/3
√d
Gradually varied flow in open channel is a/an __________ flow.
steady uniform
steady non-uniform
unsteady uniform
unsteady non-uniform
steady non-uniform
The line of action of the buoyant force acts through the
centroid of the displaced volume of fluid.
centre of gravity of a submerged body.
centroid of the volume of any floating body.
none of these.
centroid of the displaced volume of fluid.
Cavitation in a centrifugal pump can be avoided by keeping the
inlet pressure high
outlet pressure low
inlet pressure low
outlet pressure high
inlet pressure high
Vane anemometer
is an area meter.
is a variable head meter.
rotates an element at a speed determined by the velocity of the fluid in which the meter is immersed.
none of these.
rotates an element at a speed determined by the velocity of the fluid in which the meter is immersed.
The peripherial velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec.
1.8
12.4
186.2
736.4
12.4
Laminar flow is characterised by the nonexistence of
pressure fluctuation.
eddies.
deviating velocities.
all (a), (b)&(c).
all (a), (b)&(c).
The length of the tube necessary for the boundary layer to reach the centre of the tube and for fully developed flow to be established is called the __________ length.
equivalent
transition
Prandtl mixing
none of these
transition
Select the correct practical example of steady non-uniform flow.
Motion of water around a ship in a lake.
Motion of river around bridge piers.
Steadily decreasing flow through a reducing section.
Steadily increasing flow through a pipe.
Steadily decreasing flow through a reducing section.
Hydraulic diameter for non-circular ducts is equal to __________ times the area of flow divided by the perimeter.
two
three
four
eight
four
Terminal velocity is
a constant velocity with no acceleration.
a fluctuating velocity.
attained after moving one-half of total distance.
none of these.
a constant velocity with no acceleration.
Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement.
f1 = f2
f1 < f2
f1 > f2
data not sufficient to relate f1 & f2
f1 > f2
For an incompressible fluid, the bulk modulus of elasticity is
5 kg/m^3
∞ N/m^2
1 N
0 N/m
∞ N/m^2
A fluid is a substance, that
has to be kept in a closed container.
is almost incompressible.
has zero shear stress.
flows when even a small shear is applied to it.
flows when even a small shear is applied to it.
The pressure intensity is the same in all directions at a point in a fluid
only when the fluid is frictionless.
only when the fluid is at rest having zero velocity.
when there is no motion of one fluid layer relative to an adjacent layer.
regardless of the motion of one fluid layer relative to an adjacent layer.
when there is no motion of one fluid layer relative to an adjacent layer.
Which of the following must be followed by the flow of a fluid (real or ideal)?
(I) Newton’s law of viscosity.
(II) Newton’s second law of motion.
(III) The continuity equation.
(IV) Velocity of boundary layer must be zero relative to boundary.
(V) Fluid cannot penetrate a boundary.
I, II, III
II, III, V
I, II, V
II, IV, V
II, III, V
Mach number is defined as the ratio of the local flow velocity to the sonic velocity in the fluid. For what value of Mach number, the gases are considered incompressible ?
< 0.3
> 3
50
1
< 0.3
Boundary layer exists in flow
of real fluids.
over flat surfaces only.
in pipes only.
of ideal fluids only.
of real fluids.
Rubber latex is an example of __________ fluid.
dilatent
Newtonion
pseudoplastic
Bingham plastic
pseudoplastic
Velocity head on sudden enlargement in a horizontal pipe is converted into __________ head.
elevation
pressure
both (a) & (b)
neither (a) nor (b)
pressure
The frictional resistance in laminar flow does not depend on the
area of surface in contact.
flow velocity.
fluid temperature.
pressure of flow.
area of surface in contact.
A venturimeter measures the
velocity head
pressure
point velocity
none of these
none of these
Gradually varying fluid flow is an example of __________ flow.
non-steady uniform
non-steady non-uniform
steady uniform
steady non-uniform
non-steady uniform
Drag is the force component exerted on an immersed object,
passing the centroid of the body at 60°to the direction of motion.
the component being parallel to theflow direction.
the component being normal to the flow direction.
none of these.
the component being parallel to theflow direction.
To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump.
reciprocating
centrifugal
volute
rotary vacuum
reciprocating
Cocks are used to control
water
any liquid
solids
none of these
any liquid
The dimension of surface tension is
ML⁻²
MT⁻²
MLT⁻²
ML⁻²T
MT⁻²
Pick out the correct statement.
Fanning friction factor is inversely proportional to Reynolds number always.
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.
Mach number in an incompressible fluid is always unity.
Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow.
Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow.
The friction factor is
always inversely proportional to the Reynolds number.
not dimensionless.
not dependent on the roughness of the pipe.
none of these.
none of these.
Rubber latex is an example of a __________ .fluid.
pseudoplastic
bingham plastic
dilatent
Newtonion
pseudoplastic
Which of the following factors does not contribute to the pressure drop in a pipeline ?
Velocity of fluid
Size of pipe
Length of pipe and number of bends
None of these
None of these
