The velocity corresponding to Reynold number of 2800, is called
Sub-sonic velocity
Super-sonic velocity
Lower critical velocity
Higher critical velocity
Correct Answer :
D. Higher critical velocity
Related Questions
An average value of coefficient of velocity is
0.62
0.76
0.84
0.97
The total pressure on the top of a closed cylindrical vessel of radius (r) completely filled up with liquid of specific weight (w) and rotating at (ω) rad/s about its vertical axis, is
π w ω² r²/4g
π w ω² r³/4g
π w ω² r⁴/4g
π w ω² r²/2g
Cavitation will begin when
The pressure at any location reaches an absolute pressure equal to the saturated vapour pressure of the liquid
Pressure becomes more than critical pressure
Flow is increased
Pressure is increased
The weight per unit volume of a liquid at a standard temperature and pressure is called
Specific weight
Mass density
Specific gravity
None of these
When a cylindrical vessel containing liquid is revolved about its vertical axis at a constant angular velocity, the pressure
Varies as the square of the radial distance
Increases linearly as its radial distance
Increases as the square of the radial distance
Decreases as the square of the radial distance
The flow in which the particles of a fluid attain such velocities that varies from point to point in magnitude and direction as well as from instant to instant, is known as
One dimensional flow
Uniform flow
Steady flow
Turbulent flow
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 liquid used in manometers should have
Low density
High density
Low surface tension
High surface tension
Flow occurring in a pipeline when a valve is being opened is
Steady
Unsteady
Laminar
Vortex
When the water level on the downstream side of a weir is above the top surface of a weir, the weir is known as
Narrow-crested weir
Broad-crested weir
Ogee weir
Submerged weir
When the Mach number is between __________ the flow is called super-sonic flow.
1 and 2.5
2.5 and 4
4 and 6
1 and 6
When a body is placed over a liquid, it will float if
Gravitational force is equal to the up-thrust of the liquid
Gravitational force is less than the up-thrust of the liquid
Gravitational force is more than the up-thrust of the liquid
None of the above
The coefficient of viscosity may be determined by
Capillary tube method
Orifice type viscometer
Rotating cylinder method
All of these
The specific gravity of an oil whose specific weight is 7.85 kN/m3, is
0.8
1
1.2
1.6
In order to avoid tendency of separation at throat in a Venturimeter, the ratio of the diameter at throat to the diameter of pipe should be
1/16 to 1/8
1/8 to 1/4
1/4 to 1/3
1/3 to 1/2
Barometer is used to measure
Velocity of liquid
Atmospheric pressure
Pressure in pipes and channels
Difference of pressure between two points in a pipe
Practical fluids
Are viscous
Possess surface tension
Are compressible
Possess all the above properties
The center of pressure of a surface subjected to fluid pressure is the point
On the surface at which resultant pressure acts
On the surface at which gravitational force acts
At which all hydraulic forces meet
Similar to metacentre
For measuring flow by a Venturimeter, if should be installed in
Vertical line
Horizontal line
Inclined line with flow downward
In any direction and in any location
A flow in which the volume of a fluid and its density does not change during the flow is called _________ flow.
Incompressible
Compressible
Viscous
None of these
The flow which neglects changes in a transverse direction is known as
One dimensional flow
Uniform flow
Steady flow
Turbulent flow
Water is a __________ fluid.
Real
Ideal
Newtonian
Non-Newtonian
The loss of head at entrance in a pipe is (where v = Velocity of liquid in the pipe)
v²/2g
0.5v²/2g
0.375v²/2g
0.75v²/2g
Which of the following statement is wrong?
A flow whose streamline is represented by a curve is called two dimensional flow.
The total energy of a liquid particle is the sum of potential energy, kinetic energy and pressure energy.
The length of divergent portion in a Venturimeter is equal to the convergent portion.
A pitot tube is used to measure the velocity of flow at the required point in a pipe.
The conditions for the stable equilibrium of a floating body are
The metacentre should lie above the center of gravity
The center of buoyancy and the center of gravity must lie on the same vertical line
A righting couple should be formed
All the above are correct
Unit of surface tension is
Energy/unit area
Velocity/unit area
Both of the above
It has no units
The normal stress in a fluid will be constant in all directions at a point only if
It is incompressible
It has uniform viscosity
It has zero viscosity
It is at rest
If no resistance is encountered by displacement, such a substance is known as
Fluid
Water
Gas
Ideal fluid
An ideal flow of any fluid must satisfy
Pascal law
Newton's law of viscosity
Boundary layer theory
Continuity equation
The resultant upward pressure of the fluid on an immersed body due to its tendency to uplift the submerged body is called
Up-thrust
Reaction
Buoyancy
Metacentre