Fluid Mechanics Part 2 Flashcards
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/m2.
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
P1=P2
ρgh1=ρgh2
1x9.8x320=1.6x9.8xh2
h2=320/1.6=200
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
Remember: centrifugal maintenance lowest
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.
Remember: nominal hose ID
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 of these.
all of these.
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 (1)
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 ∝ N^2 : P ∝ N^3
Q ∝ N^2 : H ∝ N^3 : P ∝ N
Q ∝ N : H ∝ N^3 : P ∝ N2
Q ∝ N^3 : H ∝ N : P ∝ N^2
Q ∝ N : H ∝ N^2 : P ∝ N^3
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.