For hypersonic flow, the Mach number is
Unity
Greater than unity
Greater than 2
Greater than 4
Correct Answer :
D. Greater than 4
Related Questions
The celerity (velocity) of a pressure wave in a fluid is given by (where K = Bulk modulus, and ρ = Density of the fluid)
K.ρ
K/ρ
ρ/K
None of these
The Newton's law of resistance is based on the assumption that the
Planes of the body are completely smooth
Space around the body is completely filled with the fluid
Fluid particles do not exert any influence on one another
All of the above
If the depth of water in an open channel is less than the critical depth, the flow is called
Critical flow
Turbulent flow
Tranquil flow
Torrential flow
A tank of uniform cross-sectional area (A) containing liquid upto height (H1) has an orifice of cross-sectional area (a) at its bottom. The time required to empty the tank completely will be
(2A√H₁)/(Cd × a√2g)
(2AH₁)/(Cd × a√2g)
(2AH₁3/2)/(Cd × a√2g)
(2AH₁²)/(Cd × a√2g)
Reynold's number is the ratio of inertia force to
Pressure force
Elastic force
Gravity force
Viscous force
A fluid in equilibrium can't sustain
Tensile stress
Compressive stress
Shear stress
Bending stress
With an increase in size of tube, the rise or depression of liquid in the tube due to surface tension will
Decrease
Increase
Remain unchanged
Depend upon the characteristics of liquid
One litre of water occupies a volume of
100 cm3
250 cm3
500 cm3
1000 cm3
Froude number is significant in
Supersonics, as with projectile and jet propulsion
Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect as with ship's hulls
All of the above
The critical depth for a channel is given by (where q = Unit discharge (discharge per unit width) through the channel)
(q/g)1/2
(q²/g)1/3
(q³/g)1/4
(q⁴/g)1/5
The rise of liquid along the walls of a revolving cylinder about the initial level is __________ the depression of the liquid at the axis of rotation.
Same as
Less than
More than
None of these
The flow in a pipe is neither laminar nor turbulent when Reynold number is
Less than 2000
Between 2000 and 2800
More than 2800
None of these
The resultant upward pressure of the fluid on an immersed body is called
Up-thrust
Buoyancy
Center of pressure
All the above are correct
In an internal mouthpiece, the absolute pressure head at vena contracta is __________ the atmospheric pressure head by an amount equal to height of the liquid above the vena contracta.
Less than
More than
Equal to
None of these
The highest efficiency is obtained with a channel of __________ section.
Circular
Square
Rectangular
Trapezoidal
An ideal flow of any fluid must satisfy
Pascal law
Newton's law of viscosity
Boundary layer theory
Continuity equation
The total pressure on a horizontally immersed surface is (where w = Specific weight of the liquid, A = Area of the immersed surface, and x = Depth of the centre of gravity of the immersed surface from the liquid surface)
wA
wx
wAx
wA/x
One cubic metre of water weighs
100 litres
250 litres
500 litres
1000 litres
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 weir, generally, used as a spillway of a dam is
Narrow crested weir
Broad crested weir
Ogee weir
Submerged weir
Dynamic viscosity of most of the gases with rise in temperature
Increases
Decreases
Remain unaffected
Unpredictable
Flow occurring in a pipeline when a valve is being opened is
Steady
Unsteady
Laminar
Vortex
The factional resistance of a pipe varies approximately with __________ of the liquid.
Pressure
Velocity
Square of velocity
Cube of velocity
A uniform body 3 m long, 2 m wide and 1 m deep floats in water. If the depth of immersion is 0.6 m, then the weight of the body is
3.53 kN
33.3 kN
35.3 kN
None of these
Center of pressure on an inclined plane is
At the Centroid
Above the Centroid
Below the Centroid
At metacentre
If the atmospheric pressure on the surface of an oil tank (sp. gr. 0.8) is 0.2 kg/cm, the pressure at a depth of 50 m below the oil surface will be
2 meters of water column
3 meters of water column
5 meters of water column
6 meters of water Column
A balloon lifting in air follows the following principle
Law of gravitation
Archimedes principle
Principle of buoyancy
All of the above
The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a triangular notch is given by
dQ/Q = 3/2 × (dH/H)
dQ/Q = 2 × (dH/H)
dQ/Q = 5/2 × (dH/H)
dQ/Q = 3 × (dH/H)
A one dimensional flow is one which
Is uniform flow
Is steady uniform flow
Takes place in straight lines
Involves zero transverse component of flow
The value of coefficient of discharge is __________ the value of coefficient of velocity.
Less than
Same as
More than
None of these