Fluid Mechanics

Question: For flow past a flat plate, if x is the distance along the plate in the direction of flow, the boundary layer thickness is proportional to
[A].

x

[B].

1/x

[C].

x

[D].

1/x

Answer: Option A

Explanation:

No answer description available for this question.

Question: With increasing flow rate, the hydraulic efficiency of a centrifugal pump
[A].

monotonically decreases.

[B].

decreases and then increases.

[C].

remains constant.

[D].

increases and then decreases.

Answer: Option A

Explanation:

No answer description available for this question.

Question: A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, τ0 = 10 KPa, is shared between flat parallel plates separated by a distance of 10-3 m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is
[A].

10 KPa

[B].

20 KPa

[C].

30 KPa

[D].

40 KPa

Answer: Option B

Explanation:

No answer description available for this question.

Question: A free jet of water of cross-sectional area 0.01m2 and a velocity of 20 m/s strikes a plate and then flows in a plane parallel to the plate as shown in the figure below. The horizontal component of the force on the support is
[A].

200 N

[B].

400 N

[C].

2000 N

[D].

4000 N

Answer: Option D

Explanation:

No answer description available for this question.

Question: A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is
[A].

4.4 KPa

[B].

2.94 KPa

[C].

3.7 KPa

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.

Question: For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as
[A].

d

[B].

d2

[C].

d4

[D].

Answer: Option D

Explanation:

No answer description available for this question.

Question: Boiler feed water pump is usually a __________ pump.
[A].

reciprocating

[B].

gear

[C].

multistage centrifugal

[D].

diaphragm

Answer: Option C

Explanation:

No answer description available for this question.

Question: In the low Reynolds number region, the drag force on a sphere is proportional to
[A].

V

[B].

V2

[C].

V4

[D].

V0.5

Answer: Option A

Explanation:

No answer description available for this question.

Question: For the laminar flow of a fluid in a circular pipe of radius R, the Hagen-Poisseule equation predicts the volumetric flow rate to be proportional to
[A].

R

[B].

R2

[C].

R4

[D].

R0.5

Answer: Option C

Explanation:

No answer description available for this question.

Question: A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke’s law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity
[A].

same as that of A.

[B].

one fourth as that of A.

[C].

twice as that of A.

[D].

four times as that of A.

Answer: Option B

Explanation:

No answer description available for this question.