Category: FLUID MECHANICS Questions

In a two dimensional incompressible steady flow around an airfoil, the stream lines are 2 cm apart at a great distance from the airfoil, where the velocity is 30 m/sec. The velocity near the airfoil, where the stream lines are 1.5 cm apart, is

a) 22.5 m/sec.
b) 33 m/sec.
c) 40 m/sec.
d) 90 m/sec.
Ans: c

300+ TOP FLUID MECHANICS MCQs and Answers Pdf

100 TOP FLUID MECHANICS Multiple Choice Questions and Answers<—-CLICK HERE

86. Select the correct statement.
a) The absolute roughness of a pipe de-creases with time.
b) A pipe becomes smooth after using for long time.
c) The friction factor decreases with time.
d) The absolute roughness increases with time.
Ans: d
87. A valve is suddenly closed in a water main in wl.ich the velocity is 1 m/sec and velocity of pressure wave is 981 m/ sec. The inertia head at the valve will be
a) 1 m
b) 10m
c) 100m
d) none of the above
Ans: c
88. The speed of a pressure wave through a pipe depends upon
a) the length of pipe
b) the viscosity of fluid
c) the bulk modulus for the fluid
d) the original head
Ans: c
89. When time of closure tc = L/v0 (where L is length of pipe and v0 is speed of pressure wave), the portion of pipe length subjected to maximum head is
a) L/4
b) L/3
c) L/2
d) L
Ans: a
90. If the elevation of hydraulic grade line at the junction of three pipes is above the elevation of reservoirs B and C and below reservoir A, then the direction of flow will be
a) from reservoir A to reservoirs B and C
b) from reservoir B to reservoirs C and A
c) from reservoir C to reservoirs A and B
d) unpredictable
Ans: c

A vertical rectangular plane surface is submerged in water such that its top and bottom surfaces are 1.5 m and 6.0 m res-pectively below the free surface. The position of center of pressure below the free surface will be at a distance of

a) 3.75 m
b) 4.0 m
c) 4.2m
d) 4.5m
Ans: c