Fluid Mechanics Part 3 Flashcards
Vena-contracta formed during flow of a liquid through an orificemeter has
minimum liquid cross-section.
more diameter compared to orifice diameter.
minimum velocity of fluid stream.
none of these.
minimum liquid cross-section.
As per Newton’s law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to(where, u = fluid viscosity)
1/u
u
u2
1/u2
u
Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will __________ the gas discharge pressure.
increase
decrease
not change
exponentially decrease
increase
In continuous fluidisation
solids are completely entrained.
the pressure drop is less than that for batch fluidisation.
there is no entrainment of solids.
velocity of the fluid is very small.
solids are completely entrained.
Glass pipes can be joined by
flanges
welding
soldering
bell and spigot joint
bell and spigot joint
If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is
same in both the tubes.
greater in 1 mm dia tube.
greater in 0.5 mm dia tube.
zero in both the tubes.
greater in 0.5 mm dia tube.
For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of
2
<2
>2
44928
2
Weber number is the ratio of inertial force to __________ force.
surface tension
gravity
viscous
elastic
surface tension
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
The curve of metacentre for a floating body __________ the curve of buoyancy.
is always below
is the evolute of
intersects at right angle
is tangential to
is the evolute of
At what value of crank angle (roughly), no flow of water from or into the air vessel takes place in case of a double acting reciprocating pump ?
40 and 140
45 and 60
90 and 80
20 and 120
40 and 140
The range of a particular rotameter can be increased by
use of floats of different densities.
no means.
increasing the diameter of the float.
decreasing the diameter of the float.
use of floats of different densities.
Which of the following is dimensionless ?
Angular velocity
Fanning friction factor
Specific volume
None of these
Fanning friction factor
A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is __________ litres.
600
660
1.1
60
660
A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump.
sump
volute
vacuum
submerged
vacuum
A bed of spherical particles (specific gravity 2.5) of uniform size 1500 um is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun’s equation for the above fluid-particle system (in SI units) is given below : delta- P/L = 375 x 10^3 VOM + 10.94 x 10^6 V^2OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?
0.2
0.5
0.7
0.8
0.7
Dimension of kinematic viscosity is
MLT^-1
L^2 . T^-1
L^2T
L^2 . T^-2
L^2 . T^-1
A streamline is a line in flow field,
that is traced by all the fluid particles passing through a given point.
along which a fluid particle travels.
such that at every point on it, the velocity is tangential to it.
none of these.
such that at every point on it, the velocity is tangential to it.
While starting an axial flow pump, its delivery valve should be kept
open
closed
either open or closed
none of these
closed
__________ forces do not act in case of fluid flow.
Elastic
Tensile
Vibratory
Centrifugal
Tensile
Non-colloidal solution is an example of the __________ fluid.
non-Newtonion
Newtonion
dilatent
pseudoplastic
Newtonion
Boundary layer separation is caused by the
reduction of pressure below vapour pressure.
reduction of pressure gradient to zero.
adverse pressure gradient.
reduction of boundary layer thickness to zero.
adverse pressure gradient.
Identification of pipelines carrying different liquids and gases is done by the __________ of the pipe.
diameter
colour
altitude
none of these
colour
Pick out the correct statement.
Human blood is a Newtonion fluid.
A Newtonion fluid obeys Newton’s law of cooling.
For a non-Newtonion fluid, a straight line passes through the origin in a plot between shear stress and shear gradient.
Thin lubricating oil is an example of a non-Newtonion fluid.
A Newtonion fluid obeys Newton’s law of cooling.
What is the unit of kinematic viscosity in SI unit ?
M^2/sec
N/m^2 . sec
Kg . sec/m
None of these
M^2/sec
Hydraulic __________ works on the principle of Pascal’s law of transmission of fluid pressure.
press
turbine
pump
coupling
press
A 2” gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Δp. For the same discharge, the pressure drop across globe valve is
Δp
< Δp
> Δp
Δp²
> Δp
Remember: gate to globe > Δp
The contraction co-efficient for Borda’s mouthpiece (for frictionless fluid) is
0.1
0.5
0.94
1
0.5
Purpose of air lift pump is to
compress air.
lift compressed air.
lift water from a well by using compressed air.
lift air under negative pressure.
lift water from a well by using compressed air.
Pick out the correct statement pertaining to venturimeter.
A venturimeter with a fixed pressure drop discharges more, when the flow is vertically downward, than when the flow is vertically upward.
The co-efficient of contraction of a venturimeter is always unity.
For a fixed pressure drop, the discharge of a gas through a venturimeter is greater, when compressibility is taken into account, than when it is neglected.
none of these.
none of these.
For very low pressure and high discharge rate, the compressor used is a/an __________ compressor.
axial
reciprocating
rotary
none of these
rotary
Pumping of a corrosive liquid is generally preferred to be done by a __________ pump, as it can be made of a variety of materials including plastics.
piston
gear
positive displacement
sump
gear
What is the speed of sound (m/sec) in ordinary water ?
1500
330
1000
3000
1500
Two piping system are said to be equivalent, when the __________ are same.
fluid flow rate & friction loss
length & friction factor
diameter & friction factor
length & diameter
fluid flow rate & friction loss
Potential function is applicable only for __________ flow.
irrotational
turbulent
steady
none of these
irrotational
Which of the following exemplifies a three dimensional fluid flow ?
Fluid flow at the inlet to a nozzle
Fluid flow between parallel plates
Viscous fluid flow between converging plates
None of these
Fluid flow at the inlet to a nozzle
Volute of a centrifugal pump should be designed in a fashion, such that the
kinetic head gets converted into static head.
moving stream gradually reduces velocity.
mean velocity remains constant.
none of these.
kinetic head gets converted into static head.
The head loss due to sudden contraction is proportional to
velocity
velocity head
turbulence
none of these
velocity head
Cavitation occurs in a centrifugal pump when the suction pressure is
less than the vapour pressure of the liquid at that temperature.
greater than the vapour pressure of the liquid at that temperature.
equal to the vapour pressure.
equal to the developed head.
less than the vapour pressure of the liquid at that temperature.
An ideal plastic substance indicates no deformation, when stressed upto yield stress, but behaves like a Newtonion fluid beyond yield stress. Which of the following is an ideal plastic ?
Sewage sludge
Rubber latex
Blood
Sugar solution
Sewage sludge
The capacity of a centrifugal pump Can be increased by increasing the
impeller diameter or speed.
number of pumps and joining them in series,
number of pumps and joining them in parallel.
all of these
all of these
Which law is followed by the velocity distribution in the turbulent boundary layer?
Parabolic law
Linear law
Logarithmic law
None of these
Logarithmic law
The losses in open channel flow generally vary as the
inverse of the roughness.
first power of the roughness.
square of the velocity.
inverse square of hydraulic radius.
first power of the roughness.
Out of the following flow measuring devices, which one incurs the maximum installation cost as well as pressure loss ?
Flow nozzle
Venturimeter
Rotameter
Orificemeter
Venturimeter
For turbulent fluid flow in pipe, the expression for Prandtl one seventh power law is (where, r = pipe radius, x = distance).
V/Vmax = (x/r)^1/7
V/Vmax = (r/x)^1/7
V/Vmax = (x.r)^1/7
none of these
V/Vmax = (x/r)^1/7
Which of the following has the maximum compression ratio ?
Blower
Compressor
Vacuum pump
Fan
Vacuum pump
Scale up of agitator design requires
geometrical similarity only.
dynamic similarity only.
both geometrical and dynamic similarity.
all geometrical, dynamic and kinematic similarity.
all geometrical, dynamic and kinematic similarity.
The actual velocity at vena-contracta for flow through an orifice from a reservoir is given by
Cv . √2gH
Cc . √2gH
Cd . √2gH
Cv . Va
Cv . √2gH
The head loss in turbulent flow in pipe is proportional to (where, V = velocity of fluid through the pipe)
V²
1/V²
1/V
V
V²
Unsteady non-uniform flow is represented by flow through a/an
long pipe at constant rate.
long pipe at decreasing rate.
expanding tube at increasing rate.
expanding tube at constant rate.
expanding tube at increasing rate.
Remember: unsteady non-uniform expanding increasing
Prandtl number is a measure of the
heat conduction to viscosity of a fluid.
Cp/Cv of a fluid.
elastic force to pressure force in the fluid flow.
inertial force to elastic force in the fluid flow.
heat conduction to viscosity of a fluid.
A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, then the new head will be __________ metres.
2
4
8
5.5
2
In hindered settling, the particles are
placed farther from the wall.
not affected by other particles and the wall.
near each other,
none of these.
near each other,
A globe valve is the most suitable for applications, in which
fluid flow control is required.
fluid contains dispersed solid particles.
valve is required to be either fully open or fully closed.
one way flow is required.
fluid flow control is required.
__________ isused for measuring the static pressure exerted on the wall by a fluid flowing parallel to the wall in a pipeline.
Venturimeter
Pressure gauge
Pitot tube
Orificemeter
Pitot tube
One stoke (unit of kinematic viscosity) is equivalent to
1 cm^2/second
1 m^2/second
1 gm/cm. second
1 kg . m/second
1 cm^2/second
Air vessel of a reciprocating pump is initially filled with
atmospheric air
compressed air
water
none of these
compressed air
The ratio of inertial forces to gravity forces is called the __________ number.
Mach
Froude
Euler
Weber
Froude
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
Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m)
N^2D^3
ND^2
N^2D
N^3D^5
N^3D^5
Equivalent length of a pipe fitting is
dependent on Reynolds number.
independent of Reynolds number.
dependent on the length of the pipe.
none of these.
dependent on Reynolds number.
Buckingham-(pi) theorem states that in any physical problem including ‘n’ quantities having ‘m’ diamensions, the quantities can be arranged into __________ independent dimensionless parameters.
m
n
n-m
n/m
n-m
A fluid which has a linear relationship between the magnitude of applied shear-stress and the resulting rate of deformation is called a/an __________ fluid.
Newtonion
Non-Newtonion
ideal
incompressible
Newtonion
Existence of boundary layer in fluid flow is because of the
surface tension
fluid density
fluid viscosity
gravity forces
fluid viscosity
In case of laminar flow of fluid through a circular pipe, the
shear stress over the cross-section is proportional to the distance from the surface of the pipe.
surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder.
velocity profile varies hyperbolically and the shear stress remains constant over the cross-section.
average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius).
surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder.
Which of the following facilitates close control of flow of fluids ?
Gate valve
Globe valve
Butterfly valve
Check valve
Globe valve
For an ideal fluid flow, Reynolds number is
2100
100
0
infinite
0
Stoke’s equation is valid in the Reynolds number range
0.01 to 0.1
0.1 to 2
2 to 10
10 to 100
0.01 to 0.1
When a fluid flows over a solid surface, the
velocity is uniform at any cross-section.
velocity gradient is zero at the solid surface.
resistance between the surface & the fluid is lesser as compared to that between the fluid layers themselves.
velocity is not zero at the solid surface.
velocity gradient is zero at the solid surface.
Pick out the wrong statement about cavitation.
Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation.
Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities.
Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise.
Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades.
Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades.
The maximum delivery pressure of a reciprocating compressor may be about __________ kg/cm².
1000
2000
3000
4000
4000
The velocity for subsonic flow in a pipeline
increases in the downstream direction.
is constant.
decreases in the downstream direction.
is independent of the area of flow.
increases in the downstream direction.
Permanent pressure loss in a well designed venturimeter is about __________ percent of the venturi differential.
1
10
30
50
10
The ratio of pressure forces to inertial forces is called the __________ number.
Froude
Euler
Reynold
Mach
Euler
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
Bernoulli’s equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli’s equation ?A. Fluid flow is frictionless & irrotational. B. Fluid flow is steady. C. Fluid flow is uniform & turbulent.D. Fluid is compressible.E. Fluid is incompressible.
A, C, D
B, D, E
A, B, E
A, D, E
A, B, E
Cavitation in a centrifugal pump results from
high discharge pressure
low barometric pressure
high discharge velocity
high discharge rate
low barometric pressure
For turbulent flow of newtonion fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is
0.5
1
0.66
< 0.5
1
For flow through a venturi at a particular discharge, the correct relationships among heads at points X, Y, and Z are https://www.indiabix.com/_files/images/chemical-engineering/fluid-mechanics/11-146-1.png
h1 > h2 < h3
h1 > h2 > h3
h2 < h1 < h3
h1 < h2 < h3
h1 > h2 < h3
Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is
10√2π
5π/2
5√2π
5π/√2
5π/2
The time of oscillation of a floating body is
longer, if metacentric height is increased.
independent of the metacentric height.
dependent on the buoyant forces only.
none of these.
none of these.
What is the value of Fanning friction factor f ‘ for smooth pipe at NRe = 106 approximately ?
0.003
0.01
0.1
0.3
0.003
NRe 106 0.003
Air vessel provided in a reciprocating pump is for
increasing the acceleration head.
making the friction in pipe uniform.
decreasing the acceleration head.
none of these.
making the friction in pipe uniform.
A hydraulic accumulator comprises of
a storage device and a control valve.
a cylinder and a plunger.
two pistons and two cylinders.
a storage tank and a ram pump.
a cylinder and a plunger.
Bernoulli’s equation for steady, frictionless, continuous flow states that the __________ at all sections is same.
total pressure
total energy
velocity head
none of these
total energy
A tube is specified by its
thickness only
outer diameter only
thickness & outer diameter both
inner diameter
thickness & outer diameter both
Prandtl mixing length is
applicable to laminar flow problems.
a universal constant.
zero at the pipe wall.
none of these.
zero at the pipe wall.
The hydraulic diameter of an annulus of inner and outer radii Ri and Ro respectively is
4(Ro-Ri)
2(Ro-Ri)
Ro + Ri
2(Ro-Ri)
Ratio of inertial forces to surface tension forces is called the __________ number.
Euler
Froude
Mach
Weber
Weber
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
In open channel flow in a rectangular channel, the ratio between the critical depth and the initial depth, when a hydraulic jump occurs is
0.5
0.84
1.84
1.25
1.84
The ratio of inertial forces to viscous forces is called the __________ number.
Weber
Mach
Froude
Reynold
Reynold
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
Enamels and paints are generally __________ fluid.
reheopectic
pseudo-plastic
thixotropic
dilatant
pseudo-plastic
With the increase in depth, the hydrostatic pressure in an unaccelerated incompressible fluid (in a constant gravitational field)
decreases.
increases linearly.
increases exponentially.
remains constant.
increases linearly.
Flow measurement in an open channel is done by a/an
venturimeter
orificemeter
weir
rotameter
weir
Newton’s law of viscosity relates the
shear stress and velocity.
velocity gradient and pressure intensity.
shear stress and rate of angular deformation in a fluid.
pressure gradient and rate of angular deformation.
shear stress and rate of angular deformation in a fluid.
The equivalent diameter for fluid flow through square cross section channel of side ‘x’, for pressure drop calculation purpose is given by
4x
2x
x
√x
x
Hydraulic radius of 6” x 12” cross-section, is __________ inches.
2
0.5
1.5
none of these
2
Baffles in mixing tanks are provided to
reduce swirling and vortex formation.
increase the structural strength of the tank.
aid in rotational flow.
none of these
reduce swirling and vortex formation.
Which of the following equations is valid for laminar flow of a fluid through packed bed?
Fanning equation
Kozney - Karman equation
Hagen-Poiseuille equation
Blake-Plummer equation
Kozney - Karman equation
Forces acting on a particle settling in fluid are __________ forces.
gravitational & buoyant.
centrifugal & drag.
gravitational or centrifugal buoyant drag.
external, drag & viscous.
gravitational or centrifugal buoyant drag.
For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the
square of the radial distance.
radial distance linearly.
inverse of the radial distance.
elevation along vertical direction.
square of the radial distance.
In a dry packed bed, the pressure drop will be changed by increasing the flow rate as
V^1.8
V^-0.8
V
V^-1
V^1.8
Specific speed of a centrifugal pump depends upon the __________ head.
suction
delivery
manometric
none of these
none of these
Navier-Stokes equation is useful in the analysis of __________ fluid flow problems.
non-viscous
viscous
turbulent
rotational
viscous
The maximum discharge through a circular channel takes place, when the depth of the fluid flow is __________ times the pipe diameter.
0.25
0.5
0.66
0.95
0.95
When the head pumped against is less than the head of the fluid used for pumping, the usual device is a/an
ejector
blower
injector
airlift
airlift
Two fluids are flowing through two similar pipes of the same diameter. The Reynold’s number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will
increase
decrease
remain unchanged
data insufficient to predict relative pressure drop.
decrease
What is the value of co-efficient of discharge for square edged circular orifice (for beta = 0.3 to 0.5) ?
0.61 - 0.63
0.5 - 0.75
0.75 - 0.90
0.35 - 0.55
0.61 - 0.63
A lubricant 100 times more viscous than water would have a viscosity (in Pa.s)
0.01
0.1
1
10
0.1
Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its
inner diameter
outer diameter
thickness
neither inner nor outer diameter
neither inner nor outer diameter
I.D. of 1/4” schedule 40 pipe is 0.364”. I.D. of a 1/2” schedule 40 pipe would be __________ inch
4.728
0.5
0.622
0.474
0.5
Two liquids manometer is used for measuring small pressure differences in
liquids
gases
mixture of hydrocarbons
none of these
gases
A piezometer provided in the pipe measures
friction factor
static pressure
dynamic pressure
none of these
static pressure
The pump used for irrigation purposes is generally designed for
large capacity & high head.
large capacity & low head.
small capacity & high head.
small capacity & low head.
large capacity & low head.
In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes
less than atmospheric pressure.
more than liquid vapor pressure.
less than liquid vapor pressure.
more than atmospheric pressure.
less than liquid vapor pressure.
Pressure gradient in the pipe flow is influenced by the
diameter of pipe.
velocity of the fluid.
density & viscosity of the fluid.
all of these
all of these
__________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2.
Centrifugal
Piston
Plunger
Vane
Plunger
Boiler feed water pump is usually a __________ pump.
reciprocating
gear
multistage centrifugal
diaphragm
multistage centrifugal
Viscosity of a liquid decreases __________ with rise in temperature.
exponentially
linearly
logarithmically
none of these
logarithmically
In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is
the velocity of sound.
dependent on its cross-sectional area.
dependent on fluid viscosity.
dependent on fluid density.
the velocity of sound.
Discharge in laminar flow through a pipe varies
as the square of the radius.
inversely as the pressure drop.
inversely as the viscosity.
as the square of the diameter.
as the square of the radius.
The lift of a ballon is
increased, as it rises to a higher altitude.
due to the weight of the atmospheric air, that it displaces.
not dependent on the temperature of the atmosphere.
none of these.
due to the weight of the atmospheric air, that it displaces.
In which of the following body shapes, the pressure drag is large compared to the friction drag ?
Stream line body
Two dimensional body
Bluff body
None of these
Bluff body
Major loss in sudden contraction in pipe flow is due to
boundary friction.
flow contraction.
expansion of flow after sudden contraction.
none of these.
flow contraction.
Which of the following can be used to create a flow of gas, where no significant compression is required ?
Reciprocating compressor
Blower
Axial flow compressor
Centrifugal compressor
Blower
The ratio of actual discharge to theoretical discharge through an orifice is equal to
Cc . Cv
Cc . Cd
Cv . Cd
Cd/Cv
Cc . Cv
A free jet of water of cross-sectional area 0.01m^2 and a velocity of 20 m/s strikes a plate and then flows in a plane parallel to the plate as shown in the figure below. The horizontal component of the force on the support is
200 N
400 N
2000 N
4000 N
4000 N
Cp/Cv is termed as
adiabatic constant
Mach number
Weber number
Prandtl number
adiabatic constant
Which of the following is a Newtonian fluid?
Rubber latex
Sewage sludge
Quicksand
Non-colloidal solution
Non-colloidal solution
Which of the following valves will incur maximum pressure drop for the same discharge of water ?
Globe valve
Gate valve
Needle valve
Butterfly valve
Needle valve
Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor.
less than
more than
same as
none of these
more than
In deriving Bernoulli’s equation, fluid is assumed to be
incompressible, frictionless, steady, along a streamline.
uniform, steady, incompressible, along a streamline.
steady, density being pressure dependent, frictionless.
none of these.
incompressible, frictionless, steady, along a streamline.
Unit of mass velocity is
kg/hr
kg/m^2. hr
kg/m^2
kg/m^3. hr
kg/m^2. hr
With increase in molecular weight of the gas, the head developed by a centrifugal compressor will
decrease
increase
remain same
unpredictable
decrease
Pressure difference between two points in vessels, pipelines or in two different pipelines can be measured by a differential manometer. The pressure difference measured as the mm of water coloumn in case of mercury-water, differential manometer is equal to (where, H = difference in height of mercury column in mm).
H
12.6 H
13.6 H
14.6 H
12.6 H
The boundary layer thickness at a given section along a flat plate __________ with increasing Reynold’s number.
increases
decreases
remains same
may increase or decrease
decreases
Low specific speed of a pump implies that, it is a/an __________ pump.
axial flow
centrifugal
mixed flow
none of these
centrifugal
For pumping slurry, one can use a __________ pump.
reciprocating
diaphargm
centrifugal
pneumatic
diaphargm
Bernoulli’s equation describes the
mechanical energy balance in potential flow.
kinetic energy balance in laminar flow.
mechanical energy balance in turbulent flow.
mechanical energy balance in boundary layer.
mechanical energy balance in potential flow.
Which law/principle of solid mechanics is similar/equivalent to Newton’s law of viscosity in fluid mechanics ?
Archimedes principle.
Newton’s second law of motion.
Hooke’s law.
Newton’s third law of motion.
Hooke’s law.
When larger particles e.g., grains are subjected to fluidisation, the corresponding bed produced is termed as the __________ bed.
spouted
sluggish
boiling
teeter
spouted
Minimum fluidisation velocity for a specific system depends upon the
particle size.
fluid viscosity.
density of both the particle & the fluid.
all of these
all of these
Potential flow is characterised by the
irrotational and frictionless flow.
irrotational and frictional flow.
one in which dissipation of mechanical energy into heat occurs.
formation of eddies within the stream.
irrotational and frictionless flow.
For the production of very high vacuum, a __________ pump is normally used.
diffusion
centrifugal
jet ejector
piston
diffusion
In parallel pipe problems, the
head loss is the same through each pipe.
discharge is the same through all the pipes.
total head loss is equal to the sum of the head losses through each pipe.
none of these.
head loss is the same through each pipe.
Fluid flow through a packed bed is represented by the __________ equation.
Fanning’s
Ergun’s
Hagen-Poiseuille’s
none of these
Ergun’s
__________ is an example of axial flow impeller.
Paddle
Turbine
Propeller
all of these
Propeller
Froude number is not a factor
for Reynolds number greater than 300.
when there is no vortex formation.
for unbaffled tank.
none of these.
when there is no vortex formation.
If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor).
Q = Q1 + Q2 + Q3
V1 = V2 = V3
Q1 = Q2 = Q3
f = f1 + f2 + f3
Q = Q1 + Q2 + Q3
Horsepower requirement for given pump capacity depends upon the
specific gravity of the liquid
suction lift
discharge head
all of these
all of these
Bernoulli’s equation accounts for the
various momentums
various masses
different forms of mechanical energy
none of these
different forms of mechanical energy
__________ pumps are a group of vacuum pumps.
Hyter
Sump
Mono
Submerged
Hyter
vacuumHyter
Plunger pumps are used for
higher pressure
slurries
viscous mass
none of these
higher pressure
What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate ?
0.5
1
1.5
2
0.5
In turbulent flow, the
fluid particles move in an orderly manner.
momentum transfer is on molecular scale only.
shear stress is caused more effectively by cohesion than momentum transfer.
shear stresses are generally larger than in a similar laminar flow.
shear stresses are generally larger than in a similar laminar flow.
Momentum correction factor used in fluid flow problems accounts for the
change in direction of flow.
change in total energy.
change in pressure.
non uniform direction of velocities at inlet & outlet sections.
non uniform direction of velocities at inlet & outlet sections.
Design of the casing of centrifugal pump should be such as to minimise the
back flow through impeller
loss of kinetic head
loss of static head
none of these
loss of kinetic head
Which of the following is used for pumping crude oil from oil well ?
Single stage centrifugal pump
Gear pump
Screw pump
Duplex/triplex reciprocating pump
Duplex/triplex reciprocating pump
Remember: crude oil duplex/triplex
The energy loss in flow through ven-turimeter is less than that through flow nozzle, because in case of a flow nozzle, the
length is shorter.
throat diameter is more.
sudden expansion of flow in the downstream occurs.
distance between the throat and the inlet is more.
sudden expansion of flow in the downstream occurs.
__________ flow means the flow of incompressible fluid with no shear.
Potential
Streamline
Creep
Boundary layer
Potential
The continuity equation
relates mass flow rate along a stream tube.
relates work and energy.
stipulates that Newton’s second law of motion must be satisfied at every point in the fluid.
none of these.
relates mass flow rate along a stream tube.
The energy loss over a length of pipeline according to Darcy-Weisbach equation for pipe flow is…..the mean velocity of flow.
directly proportional to
directly proportional to square of
inversely proportional to
inversely proportional to square of
directly proportional to square of
Pressure drop in a packed bed for laminar flow is given by the __________ equation.
Kozney-Karman
Blake-Plummer
Leva’s
Fanning friction factor
Kozney-Karman
The fluid velocity varies as the cube of the cylinderical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid.
Newtonion
pseudoplastic
dilatent
Bingham plastic
pseudoplastic
Stoke’s law is valid, when NRe, p is less than
2
100
2100
700
2
Froude number is the ratio of
shear stress to gravitational stress.
drag stress to shear stress.
inertial stress to shear stress.
inertial stress to gravitational stress.
inertial stress to gravitational stress.
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
Normal depth in open channel flow is the depth of flow in the channel
corresponding to uniform flow.
measured normal to the channel bed.
corresponding to steady flow.
none of these.
corresponding to uniform flow.
Which of the following flow measuring devices is an area meter ?
Venturimeter
Orifice meter
Anemometer
Rotameter
Rotameter
With decrease in particle size to be fluidised by a particular fluid, the operating range of fluidisation velocity
widens
squeezes
does not change
unpredictable from the data
does not change
Diaphragm valves are used for handling __________ fluids.
corrosive
viscous
non-Newtonion
solid suspended
corrosive
The schedule number of a pipe is an indication of its
size
roughness
material density
wall thickness
wall thickness
Minimum porosity for fluidisation is
that corresponding to static bed.
that corresponding to completely fluidised bed.
the porosity of the bed when true fluidisation begins.
less than that of the’ static bed.
the porosity of the bed when true fluidisation begins.
A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now
increase
decrease
remain same
data insufficient to predict
decrease
Steady non-uniform flow is exemplified by flow through a/an
long pipe at constant rate.
long pipe at decreasing rate.
expanding tube at increasing rate.
expanding tube at constant rate.
expanding tube at constant rate.
Remember:
steady - constant
non-uniform - expanding
The maximum depth from which a centrifugal pump can draw water is
dependent on the speed of the pump.
dependent on the power of the pump.
34 feet.
150 feet.
34 feet.
Hot wire anemometer is used to measure the
velocity of liquids.
temperature of liquids.
velocity of gases.
pressure of liquids.
velocity of gases.
Propeller type centrifugal pumps are most suitable for
high capacity at high heads.
high capacity at low heads.
low capacity at high heads.
low capacity at low heads.
high capacity at low heads.
The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid.
Newtonion
dilatant
pseudoplastic
non-Newtonion
Newtonion
Momentum transfer in laminar flow of fluids results due to the
viscosity
density
velocity gradient
none of these
velocity gradient
The capillary rise of mercury is maximum in glass tube of dia __________ mm.
0.5
1
2
5
0.5
Diaphragm pumps are used to transport
solids
liquids
fluids
slurries
slurries
For steady ideal fluid flow, the Bernoulli’s equation states that the
velocity is constant along a stream line.
energy is constant throughout the fluid
energy is constant along a stream line, but may vary across stream lines
none of these
energy is constant along a stream line, but may vary across stream lines
In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller.
speed of
diameter of
fluid velocity leaving
all of these
all of these
