When the Mach number is less than unity, the flow is called
Sub-sonic flow
Sonic flow
Super-sonic flow
Hyper-sonic flow
Correct Answer :
A. Sub-sonic flow
Related Questions
The velocity corresponding to Reynold number of 2800, is called
Sub-sonic velocity
Super-sonic velocity
Lower critical velocity
Higher critical velocity
The discharge through a channel of rectangular section will be maximum, if
Its depth is twice the breadth
Its breadth is twice the depth
Its depth is thrice the breadth
Its breadth is thrice the depth
A hemispherical tank of radius (R) has an orifice of cross-sectional area (a) at its bottom and is full of liquid. The time required to empty the tank completely is
14π R1/2/15Cd × a √(2g)
14π R3/2/15Cd × a √(2g)
14π R5/2/15Cd × a √(2g)
14π R7/2/15Cd × a √(2g)
During the opening of a valve in a pipe line, the flow is
Steady
Unsteady
Uniform
Laminar
In one dimensional flow, the flow
Is steady and uniform
Takes place in straight line
Takes place in curve
Takes place in one direction
A fluid is said to be ideal, if it is
Incompressible
Viscous and incompressible
Inviscous and compressible
Inviscous and incompressible
The discharge through a siphon spillway is
Cd × a × √(2gH)
Cd × a × √(2g) × H3/2
Cd × a × √(2g) × H2
Cd × a × √(2g) × H5/2
A flow is called hyper-sonic, if the Mach number is
Less than unity
Unity
Between 1 and 6
None of these
Piezometer is used to measure
Pressure in pipe, channels etc.
Atmospheric pressure
Very low pressures
Difference of pressure between two points
The flow which neglects changes in a transverse direction is known as
One dimensional flow
Uniform flow
Steady flow
Turbulent flow
The ratio of absolute viscosity to mass density is known as
Specific viscosity
Viscosity index
Kinematic viscosity
Coefficient of viscosity
The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a rectangular notch is given by
dQ/Q = (1/2) × (dH/H)
dQ/Q = (3/4) × (dH/H)
dQ/Q = (dH/H)
dQ/Q = (3/2) × (dH/H)
The units of dynamic or absolute viscosity are
Metres² per sec
kg sec/meter
Newton-sec per meter
Newton-sec² per meter
An odd shaped body weighing 7.5 kg and occupying 0.01 m3 volume will be completely submerged in a fluid having specific gravity of
1
1.2
0.8
0.75
Choose the wrong statement
The horizontal component of the hydrostatic force on any surface is equal to the normal force on the vertical projection of the surface
The horizontal component acts through the center of pressure for the vertical projection
The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area
The vertical component passes through the center of pressure of the volume
The depth of the centre of pressure on a vertical rectangular gate 8 m wide and 6 m high, when the water surface coincides with the top of the gate, is
2.4 m
3.0 m
4.0 m
5.0 m
The value of the coefficient of compressibility for water at ordinary pressure and temperature in kg/cm is equal to
2100
2700
10,000
21,000
One poise is equal to
0.1 N-s/m2
1 N-s/m2
10 N-s/m2
100 N-s/m2
When a cylindrical vessel containing liquid is resolved, the surface of the liquid takes the shape of
A triangle
A paraboloid
An ellipse
None of these
Surface tension has the units of
Newton-sec/m
Newton-m/sec
Newton/m
Newton
In a broad-crested weir, the discharge is maximum if the head of water on the downstream side of weir is __________ the head of water on the upstream side of weir.
Equal to
One-third
Two-third
Three-fourth
True one-dimensional flow occurs when
The direction and magnitude of the velocity at all points are identical
The velocity of successive fluid particles, at any point, is the same at successive periods of time
The magnitude and direction of the velocity do not change from point to point in the fluid
The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
Pitot tube is used for measurement of
Pressure
Flow
Velocity
Discharge
A piece of metal of specific gravity 7 floats in mercury of specific gravity 13.6. What fraction of its volume is under mercury?
0.5
0.4
0.515
0.5
Mercury does not wet glass. This is due to property of liquid known as
Adhesion
Cohesion
Surface tension
Viscosity
One stoke is equal to
10-2 m2/s
10-3 m2/s
10-4 m2/s
10-6 m2/s
The kinematic viscosity is the
Ratio of absolute viscosity to the density of the liquid
Ratio of density of the liquid to the absolute viscosity
Product of absolute viscosity and density of the liquid
Product of absolute viscosity and mass of the liquid
Property of a fluid by which its own molecules are attracted is called
Adhesion
Cohesion
Viscosity
Compressibility
The siphon will work satisfactorily, if the minimum pressure in the pipe is __________ vapour pressure of liquid.
Equal to
Less than
More than
None of these
When a plate is immersed in a liquid parallel to the flow, it will be subjected to a pressure __________ that if the same plate is immersed perpendicular to the flow.
Less than
More than
Equal to
None of these