Fluid Mechanics Part 4 Flashcards
A hydraulic press has a ram of 10 cms in diameter and a plunger of 1 cm in diameter. The force required on the plunger to raise a weight of 10 tons on the ram is __________ kg.
10
100
1000
10000
100
Choose the set of pressure intensities that are equivalent.
4.33 psi, 10 ft. of water, 8.83 inches of Hg.
4.33 psi, 10 ft. of water, 20.7 inches of Hg.
10 psi, 19.7 ft. of water, 23.3 inches of Hg.
10 psi, 19.7 ft. of water, 5.3 inches of Hg.
4.33 psi, 10 ft. of water, 8.83 inches of Hg.
Pick out the wrong statement about a streamline.
It is always parallel to the main direction of the fluid flow.
It is a line across which there is no flow and it is equivalent to a rigid boundary.
Streamlines intersect at isolated point of zero velocity and infintie velocity.
The fluid lying between any two streamlines can be considered to be in isolation and the streamline spacing varies inversely as the velocity.
It is always parallel to the main direction of the fluid flow.
The most serious disadvantage of an orificemeter is that
it is not very accurate.
it is very costly.
most of the pressure drop is not recoverable.
it is not suitable for measuring gas flow.
most of the pressure drop is not recoverable.
The discharge through a rectangular weir varies as
H^1/2
H^5/2
H^2/5
H^3/2
H^3/2
In case of supersonic flow of a fluid through pipeline, the ‘Mach number’ is
0
1
< 1
> 1
> 1
A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpmHead = 8 metresFlow = 1000 litres/minutes.If its speed is halved, the power consumed now will be __________ hp.
0.5
2
4
1
0.5
Transition length for turbulent flow in smooth pipe is equal to __________ times the pipe diameter.
0.5
5
50
100
50
Disc compensators are provided in large diameter fuel gas carrying pipelines to
keep the pipe in proper orientation.
make the pipe joint leak-proof.
account for contraction/expansion of pipe due to temperature changes of the surroundings.
account for the pressure variation side the pipeline.
account for contraction/expansion of pipe due to temperature changes of the surroundings.
Discharge from a 24 inch pipe of water at 10 ft/sec will be __________ ft3/sec.
7.65
32.36
48.22
125.6
125.6
Paper pulp is an example of __________ fluid.
dilatant
bingham plastic
Newtonion
pseudoplastic
bingham plastic
The ratio of the depth of flow to the diameter of the channel for maximum discharge in a circular channel in open channel flow is
0.1
0.55
0.95
1.85
0.95
A conical tank with a bottom opening of cross-sectional area A is filled with water and is mounted on supports as shown in the figure. What is the force F with which plate X must be pushed up to prevent water from leaking ? Assume that the density of air is negligible as compared to the density of water ρL. (1)
ρL . Vg
ρL . A.Hg
ρL . Vg/2
ρL .Vg/3
ρL . A.Hg
A relief valve
provides back pressure for a cylinder.
unloads a pump.
is a directional control valve.
none of these.
is a directional control valve.
An isentropic process is the one, in which
pv = constant
pvr = constant
pvr = constant, and process is reversible
none of these
pvr = constant, and process is reversible
The distribution of shear stress in a stream of fluid in a circular tube is
linear with radius for turbulent flow only.
linear with radius for laminar flow only.
linear with radius for both laminar & turbulent flow.
parabolic with radius for both laminar & turbulent flow.
linear with radius for both laminar & turbulent flow.
For motion of spherical particles in a stationary fluid, the drag co-efficient in hindered settling compared to that in free settling is
more
less
equal
more or less, depending on the type of particle
more
Specific speed of a centrifugal pump relates it with another pump having the
dynamic similarity
same efficiency
same speed
geometrical similarity
dynamic similarity
Air vessel fitted to a reciprocating pump
increases the work done.
decreases the work done.
causes cavitation.
results in non-uniform discharge.
decreases the work done.
Deformation drag, which is caused by widespread deformation of fluid around the immersed body
occurs when NRe is very small.
is primarily a friction drag.
is independent of body length.
depends mainly on cross-sectional shape.
occurs when NRe is very small.
In isotropic turbulence, the __________ are equal to each other.
temporal velocity components
mean square of velocity fluctuations in the three co-ordinate directions
root mean square of velocity fluctuations in the three co-ordinate directions
none of these
mean square of velocity fluctuations in the three co-ordinate directions
Viscosity of water is about __________ times that of air at room temperature.
15
55
155
1050
55
Net positive suction head (NPSH) of a centrifugal pump must be
greater than the vapour pressure of the liquid.
less than the vapour pressure of the liquid.
equal to the vapour pressure of the liquid.
less than barometric pressure.
greater than the vapour pressure of the liquid.
Actual lift of a pump is always less than the theoretical lift and is limited by the
specific gravity & temperature of the liquid.
leakage & pressure decreasing at higher elevations.
frictional resistance through pipes, fittings & passages.
all of these
all of these