The velocity profile exhibited by laminar flow of Newtonion fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an __________ with the apex at the centre line of the pipe.
-
hyperbola -
parabola -
semi-circle -
semi-ellipse
One dimensional flow implies
-
flow in a straight line. -
steady uniform flow. -
unsteady uniform flow. -
a flow which does not account for changes in transverse direction.
Power required for mixing Newtonion fluids is a function of the
-
speed of impeller, diameter of impeller & viscosity. -
density & viscosity of fluid only. -
density of fluid, viscosity of fluid & impeller dia only. -
none of these.
Propellers are
-
axial flow mixers. -
low speed impeller. -
used for mixingliquids of high viscosity. -
radial flow mixers.
The discharge through a semi-circular weir varies as (where, H = Head of liquid.)
-
H -
H2 -
H3/2 -
H1/2
Flow rate of high velocity flue gas discharged through a stack to the atmosphere can be most conveniently measured by a
-
pitot tube -
manometer -
rotameter -
none of these
In case of coutte flow, the fluid flow is between two large flat parallel plates with
-
top plate moving and the bottom plate fixed. -
bottom plate moving and the top plate fixed. -
both the plates fixed. -
both the plates moving.
The co-efficient of discharge of an orificemeter is a function of
-
Reynolds number at the orifice. -
ratio of orifice dia to pipe dia. -
both (a) and (b). -
none of the above parameters, and has a constant value of 0.61.
In which of the following cases, it is possible for flow to occur from low pressure to high pressure ?
-
Flow of liquid upward in a vertical pipe. -
Flow through a converging section. -
Flow of air downward in a pipe. -
Impossible in a constant cross-section conduit.
Multistage compressors are used in industry, because they
-
reduce the cost of compressor. -
reduce the size requirement, -
resemble closely to isothermal compression. -
are easy to control.
The hydrodynamic and thermal boundary layers will merge, when
-
Prandtl number is one. -
Schmidt number tends to infinity. -
Nusselt number tends to infinity. -
Archimedes number is greater than 10000.
Critical velocity in a pipe flow
-
increases as fluid viscosity increases. -
increases as pipe diameter increases. -
independent of fluid density. -
none of these.
The inherent characteristic of an equal percentage valve relating flow rate 'q' with valve stem movement 'x' are described by the equation
The velocity profile exhibited by laminar flow of Newtonion fluids is such that the velocity distribution w.r.t. radius of the circular pipe is a/an __________ with the apex at the centre line of the pipe.
-
hyperbola -
parabola -
semi-circle -
semi-ellipse
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.
Purpose of relief valve in a reciprocating pump is to
-
protect the pump against developing excessive pressure. -
facilitate unidirectional flow of liquid. -
reduce the discharge pressure. -
control the rate of discharge.
Which of the following can be used for the direct measurement of volumetric flow rate of slurry ?
-
Venturimeter -
Orificemeter -
Rotameter -
Pitot tube
Pick out the wrong statement.
-
In a static mass of liquid, the pressure at a point is the same for all liquids. -
Pressure decreases exponentially with elevation in an isothermal atmosphere. -
Atmospheric pressure = absolute pressure-gage pressure. -
As per Pascal's law, the pressure at a point in a static or uniformly moving fluid is equal in all directions.
Select the correct statement.
-
The discharge through a venturimeter depends upon Δp only and is independent of orientation of the meter. -
A venturimeter with a given gage difference discharges at a greater rate, when the flow is vertically downward through it, than when the flow is vertically upward. -
For a given pressure difference, the discharge of gas is greater through a venturimeter, when compressibility is taken into account, than when it is neglected. -
The overall pressure loss is the same in a given pipe line, whether a venturimeter or a nozzle with the same throat dia is used.
A pipe is defined as 'hydraulically smooth', if the friction factor
-
is not a function of Reynolds number. -
for a given Reynolds number remains constant even on further smoothening of the pipe. -
is zero irrespective of the Reynolds number. -
none of these.
What is the maximum theoretical suction lift (metres) of a reciprocating pump ?
-
5 -
10 -
50 -
100
The terminal velocity of a particle moving through a fluid varies as dpn. The value of n is equal to __________ in Stoke's law regime.
-
2 -
1 -
0.5 -
1.5
The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is
-
parabolic -
flat -
flat near the wall and parabolic in the middle -
parabolic near the wall and flat in the middle.
In case of a __________ the energy of flow is considerably decreased downstream of the machine.
-
blower -
turbine -
centrifugal pump -
centrifugal fan
Poise is converted into stoke by
-
multiplying with density (gm/c.c). -
dividing by density (gm/c.c). -
multiplying with specific gravity. -
dividing by specific gravity.
As per Newton's law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to(where, μ = fluid viscosity)
-
1/μ -
μ -
μ2 -
1/μ2
The nominal size of a hose pipe is specified by its
-
I.D. -
O.D. -
thickness -
none of these
If the head over the triangular notch is doubled, the discharge will increase by __________ times.
-
2 -
2.828 -
5.657 -
4
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
The momentum correction factor for the velocity distribution of laminar flow is
-
1.3 -
1.66 -
2.5 -
none of these
In case of turbulent flow of fluid through a circular pipe, the
-
mean flow velocity is about 0.5 times the maximum velocity. -
velocity profile becomes flatter and flatter with increasing Reynolds number. -
point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius). -
skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more.
A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is
-
5 -
14.1 -
56.22 -
28.2
Delivery of insufficient quantity of liquid by a pump may be caused by
-
air leak in the inlet -
low rpm -
too high a lift -
all (a), (b) and (c)
Function of air vessel provided in a reciprocating pump is to
-
reduce discharge fluctuation. -
reduce the danger of cavitation. -
avoid the necessity of priming. -
increase the pump efficiency.
The percentage slip in a reciprocating pump set is given by the % of (where, Q1 = actual discharge Q2 = theoretical discharge)
-
Q1/Q2 
-
Q2/Q1
-
-
Fanning friction factor for laminar flow of fluid in a circular pipe is
-
not a function of the roughness of pipe wall. -
inversely proportional to Reynolds number. -
both (a) & (b). -
neither (a) nor (b).
The unit of dynamic viscosity in SI unit is
-
kg/m . sec -
N/m2 -
m2 /sec. -
m/N. sec.
With increase in the shear rate, the apparent viscosity of pseudoplastic fluids
-
increases -
decreases -
remains same -
may increase or decrease; depends on the magnitude of shear rate
The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop fo __________ fluid.
-
dilatant -
pseudoplastic -
Bingham plastic -
Newtonion
Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will __________ the gas discharge pressure.
-
increase -
decrease -
not change -
exponentially decrease
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.
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.
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).
Friction factor for a hydraulically smooth pipe at NRe =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.
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
For the same flow rate of a fluid, the pressure drop is the least for
-
venturimeter -
orificemeter -
flow-nozzle -
Δp is same for all
The valve commonly used in pipes larger thandia is a
-
globe valve -
plug-cock -
gate valve -
check valve
For the same terminal conditions and valve size, the pressure drop in a fully opened globe valve as compared to that in a gate valve is
-
more -
less -
equal -
either (a) or (b); depends on the viscosity of the fluid
Quicksand is an example of a __________ fluid.
-
bingham plastic -
dilatent -
Newtonion -
pseudoplastic
Fluid resistance to shear depends upon its
-
rate of transfer of molecular momentum. -
cohesion. -
both (a) and (b). -
neither (a) nor (b).