Fluid Mechanics

Question: In the complete turbulence zone (in rough pipes), the
[A].

rough and smooth pipes have the same friction factor.

[B].

laminar film covers the roughness projections.

[C].

friction factor depends upon NRe only.

[D].

friction factor is independent of the relative roughness.

Answer: Option D

Explanation:

No answer description available for this question.

Question: In turbulent flow, a rough pipe has the same friction factor as a smooth pipe
[A].

in the zone of complete turbulence.

[B].

when the roughness projections are much smaller than the thickness of the laminar film.

[C].

everywhere in the transition zone.

[D].

when the friction factor is independent of the Reynold’s number.

Answer: Option B

Explanation:

No answer description available for this question.

Question: Boundary layer separation occurs when the
[A].

pressure reaches a minimum.

[B].

cross-section of the channel is reduced.

[C].

valve is closed in a pipeline.

[D].

velocity of sound is reached.

Answer: Option B

Explanation:

No answer description available for this question.

Question: Boundary layer separation is caused by the
[A].

reduction of pressure to vapour pressure.

[B].

boundary layer thickness reducing to zero.

[C].

adverse pressure gradient.

[D].

reduction of pressure gradient to zero.

Answer: Option C

Explanation:

No answer description available for this question.

Question: In laminar flow through a round tube, the discharge varies
[A].

linearly as the viscosity.

[B].

inversely as the pressure drop.

[C].

inversely as the viscosity.

[D].

as the square of the radius.

Answer: Option C

Explanation:

No answer description available for this question.

Question: A streamline is
[A].

the line connecting the mid-points of flow cross-sections.

[B].

defined for uniform flow only.

[C].

drawn normal to the velocity vector at every point.

[D].

always the path of a particle.

Answer: Option C

Explanation:

No answer description available for this question.

Question: For ideally incompressible fluid, the Mach number will be
[A].

1.5

[B].

1

[C].

0

[D].

5

Answer: Option B

Explanation:

No answer description available for this question.

Question: Enamels and paints are generally __________ fluid.
[A].

reheopectic

[B].

pseudo-plastic

[C].

thixotropic

[D].

dilatant

Answer: Option B

Explanation:

No answer description available for this question.

Question: A rotameter works on the principle of __________ pressure drop.
[A].

constant

[B].

variable

[C].

both (a) & (b)

[D].

neither (a) nor (b)

Answer: Option A

Explanation:

No answer description available for this question.

Question: Bernoulli’s equation is dependent on the
[A].

first law of thermodynamics.

[B].

third law of thermodynamics.

[C].

law of conservation of momentum.

[D].

none of these.

Answer: Option D

Explanation:

No answer description available for this question.