21) When March number is more than 6, the flow is called
a) subsonic flow
b) sonic flow
c) supersonic flow
d) hypersonic flow
22) The integral momentum equation requires the following assumption in the flow
a) uniform
b) unidirectional
c) incompressible
d) steady
23) The flow of water in a wash hand basin when it is being emptied through a central opening, is an example of
a) free vortex
b) forced vortex
c) rotational vortex
d) Rankine vortex
24) A triangular notch is a more accurate measuring device than a rectangular notch
a) for low flow rates
b) for high flow rates
c) for medium flow rates
d) for all flow rates
25) The pressure at the summit of a siphon is
a) equal to atmospheric
b) less than atmospheric
c) more than atmospheric
d) None of the above
26) The boundary layer exists in
a) flow of ideal fluid
b) flow of real fluid
c) only in pipe flow
d) only flow over flat plate
27) The maximum thickness of boundary layer in a pipe of radius r is
a) 0
b) r/2
c) r
d) 2r
28) The ratio of average velocity to maximum velocity for steady laminar flow in circular pipes is
a) ½
b) 2/3
c) 3/2
d) 2
29) The distance from pipe boundary, at which the turbulent shear stress is one-third the wall shear stress, is
a) 1/3 R
b) ½ R
c) 2/3 R
d) ¾ R
30) In a wide rectangular channel if the normal depth is increased by 20%, the percentage increase in the discharge will be
a) 35%
b) 40%
c) 33.3%
d) 66.6%