Internal Flow of Fluid - Mechanical Engineering (MCQ) questions and answers

1)   What is the ratio of maximum velocity to average velocity, when the fluid is passing through two parallel plates and flow is laminar?

a. 3/2
b. 2/3
c. 4/3
d. 3/4
Answer  Explanation 

ANSWER: 3/4

Explanation:
No explanation is available for this question!


2)   Below diagram shows the velocity distribution of fluid flow through a pipe. Flow is laminar.
What is the ratio of maximum velocity to average velocity?


a. 1
b. 2
c. 4
d. 3.14
Answer  Explanation 

ANSWER: 2

Explanation:
No explanation is available for this question!


3)   What is temporal mean velocity?

a. The average of velocities at a point over a certain period of time
b. The average of velocities of a single particle over different locations in a fluid flow
c. None of the above

Answer  Explanation 

ANSWER: The average of velocities at a point over a certain period of time

Explanation:
No explanation is available for this question!


4)   Friction factor for laminar flow is given by

a. (Re /64)
b. (64 / Re)
c. (Re / 16)
d. (16 / Re)
Answer  Explanation 

ANSWER: (64 / Re)

Explanation:
No explanation is available for this question!


5)   Kinematic eddy viscosity (ε) is the ratio of

a. eddy viscosity (η) to dynamic viscosity (μ)
b. eddy viscosity (η) to kinematic viscosity (ν)
c. kinematic viscosity to eddy viscosity (η)
d. eddy viscosity (η) to mass density (ρ)
Answer  Explanation 

ANSWER: eddy viscosity (η) to mass density (ρ)

Explanation:
No explanation is available for this question!


6)   Magnitude of eddy viscosity for laminar flow is

a. less than zero
b. zero
c. greater than zero
d. unpredictable
Answer  Explanation 

ANSWER: zero

Explanation:
No explanation is available for this question!


7)   Shear stress in a turbulent flow is given by the formula

τ = η (du / dy)

Where η (eta) is,


a. eddy viscosity
b. apparent viscosity
c. virtual viscosity
d. all of the above
Answer  Explanation 

ANSWER: all of the above

Explanation:
No explanation is available for this question!


8)   Coefficient of friction for laminar flow is given as

Where,
Re = Reynold's number


a. (Re / 32)
b. (32 / Re)
c. (Re / 16)
d. (16 / Re)
Answer  Explanation 

ANSWER: (16 / Re)

Explanation:
No explanation is available for this question!


9)   How should be the viscosity of the flowing fluid for laminar flow?

a. viscosity of the fluid should be as low as possible, for laminar flow
b. viscosity of the fluid should be as high as possible, for laminar flow
c. change in viscosity of the flowing fluid does not affect its flow
d. unpredictable
Answer  Explanation 

ANSWER: viscosity of the fluid should be as high as possible, for laminar flow

Explanation:
No explanation is available for this question!


10)   The flow of fluid will be laminar when,

a. Reynold's number is less than 2000
b. the density of the fluid is low
c. both a. and b.
d. none of the above
Answer  Explanation 

ANSWER: both a. and b.

Explanation:
No explanation is available for this question!