Fluid Mechanics

Question: In case of turbulent flow of fluid through a circular pipe, the
[A].

mean flow velocity is about 0.5 times the maximum velocity.

[B].

velocity profile becomes flatter and flatter with increasing Reynolds number.

[C].

point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius).

[D].

skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more.

Answer: Option D

Explanation:

No answer description available for this question.

Question: In case of laminar flow of fluid through a circular pipe, the
[A].

shear stress over the cross-section is proportional to the distance from the surface of the pipe.

[B].

surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder.

[C].

velocity profile varies hyperbolically and the shear stress remains constant over the cross-section.

[D].

average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius).

Answer: Option B

Explanation:

No answer description available for this question.

Question: Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid
[A].

lies above the centroid of the plane surface.

[B].

is independent of the specific weight of the fluid.

[C].

is different for different fluids.

[D].

is at the centroid of the plane surface.

Answer: Option B

Explanation:

No answer description available for this question.

Question: __________ isused for measuring the static pressure exerted on the wall by a fluid flowing parallel to the wall in a pipeline.
[A].

Venturimeter

[B].

Pressure gauge

[C].

Pitot tube

[D].

Orificemeter

Answer: Option C

Explanation:

No answer description available for this question.

Question: An ideal plastic substance indicates no deformation, when stressed upto yield stress, but behaves like a Newtonion fluid beyond yield stress. Which of the following is an ideal plastic ?
[A].

Sewage sludge

[B].

Rubber latex

[C].

Blood

[D].

Sugar solution

Answer: Option A

Explanation:

No answer description available for this question.

Question: Colebrook equation for friction factor in turbulent flow is given by, . It reduces to Nikuradse equation for a value of equal to
[A].

0

[B].

1

[C].

∞

[D].

0.5

Answer: Option B

Explanation:

No answer description available for this question.

Question: N2Re/NFr is called the __________ number.
[A].

Brinkman

[B].

Galileo

[C].

Archimedes

[D].

Euler

Answer: Option B

Explanation:

No answer description available for this question.

Question: Minimum porosity for fluidisation is
[A].

that corresponding to static bed.

[B].

that corresponding to completely fluidised bed.

[C].

the porosity of the bed when true fluidisation begins.

[D].

less than that of the’ static bed.

Answer: Option C

Explanation:

No answer description available for this question.

Question: Isothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the
[A].

wall roughness.

[B].

Reynolds number.

[C].

both (a) & (b).

[D].

neither (a) nor (b).

Answer: Option C

Explanation:

No answer description available for this question.

Question: Applicability of Bernoulli’s equation is limited to a/an __________ fluid, that does not exchange shaft work with the surroundings.
[A].

incompressible

[B].

non-viscous

[C].

both (a) and (b)

[D].

neither (a) nor (b)

Answer: Option C

Explanation:

No answer description available for this question.