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211.

Select a common dimensionless parameter in fluid mechanics from the following:

212.

The boundary layer separation takes place if

A.	Pressure gradient is zero	B.	Pressure gradient is positive
C.	Pressure gradient is negative	D.	None of the above

213.

The surface tension has the units

214.

Separation is caused by

A.	Reduction of pressure to vapour pressure	B.	Reduction of pressure gradient to zero
C.	An adverse pressure gradient	D.	The boundary layer thickness reducing to zero
E.	None of these answers

215.

The wake

A.	Is a region of high pressure	B.	Is the principal cause of skin friction
C.	Always occurs when deformation drag predominates	D.	Always occurs after a separation point
E.	Is none of these answers

216.

The magnitude of water hammer depends on

A.	The length of pipeline	B.	The speed at which the valve is closed
C.	To elastic properties of the liquid flowing through the pipe	D.	The elastic properties of the pipe material
E.	All of the above

217.

When power is transmitted through a considerable distance by means of water under pressure, the maximum power is transmitted when

A.	Frictional loss of head is one third of the total head supplied	B.	Frictional loss of head is half of the total head supplied
C.	Frictional loss of head is 10% of the total head	D.	Eficiency of transmission is 75%
E.	Loss in transmission is 17.7%.

218.

Hammer blow in pipe occurs when

A.	Pipe is hit with hammer	B.	Pipe bursts under high fluid pressure
C.	Excessive leakage occurs in pipe	D.	Flow of fluid through pipe is gradually brought to rest by the closing of valve
E.	Flow of fluid through pipe is suddenly brought to rest by the closing of the valve

219.

The ratio inertia forces/surface tension force gives a non-dimensional number known as

220.

The ratio of inertia force to pressure forces is related with a non-dimensional number known as