Fluid Mechanics

Question: Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, σ = surface tension of mercury)
[A].

d

[B].

1/d

[C].

σ

[D].

l/σ

Answer: Option C

Explanation:

No answer description available for this question.

Question: Dimension of surface tension is(where, F = force, L = length)
[A].

FL-1

[B].

F-1 . L

[C].

F.L-2

[D].

F-2 . L

Answer: Option A

Explanation:

No answer description available for this question.

Question: Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.)
[A].

d

[B].

d1/3

[C].

d2

[D].

d2/3

Answer: Option A

Explanation:

No answer description available for this question.

Question: Drag force on the float of a rotameter is(where Q = flow rate of the )
[A].

∝Q

[B].

∝Q

[C].

∝Q2

[D].

constant

Answer: Option D

Explanation:

No answer description available for this question.

Question: Fanning friction factor for laminar flow of fluid in a circular pipe is
[A].

not a function of the roughness of pipe wall.

[B].

inversely proportional to Reynolds number.

[C].

both (a) & (b).

[D].

neither (a) nor (b).

Answer: Option C

Explanation:

No answer description available for this question.

Question: At low Reynolds number
[A].

viscous forces are unimportant.

[B].

viscous forces control.

[C].

viscous forces control and inertial forces are unimportant.

[D].

gravity forces control.

Answer: Option C

Explanation:

No answer description available for this question.

Question: A pipe is defined as ‘hydraulically smooth’, if the friction factor
[A].

is not a function of Reynolds number.

[B].

for a given Reynolds number remains constant even on further smoothening of the pipe.

[C].

is zero irrespective of the Reynolds number.

[D].

none of these.

Answer: Option B

Explanation:

No answer description available for this question.

Question: Fluid flow through a packed bed is represented by the __________ equation.
[A].

Fanning’s

[B].

Ergun’s

[C].

Hagen-Poiseuille’s

[D].

none of these

Answer: Option B

Explanation:

No answer description available for this question.

Question: Mercury is an ideal barometric fluid mainly due to its
[A].

high density.

[B].

low compressibility.

[C].

low capillary action.

[D].

very low vapor pressure.

Answer: Option D

Explanation:

No answer description available for this question.

Question: In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature.
[A].

lower than

[B].

higher than

[C].

equal to

[D].

none of these

Answer: Option B

Explanation:

No answer description available for this question.