Fluid Mechanics Questions and Answers – Types of Flow in Channels

This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Types of Flow in Channels”.

1. The flow characteristics of a channel does not change with time at any point. What type of flow is it?
a) Steady flow
b) Uniform flow
c) Laminar flow
d) Turbulent flow
View Answer

Answer: a
Explanation: The flow characteristics unchanged with time is a steady flow, characteristics unchanged with space is a uniform flow. Laminar and turbulent flows are classified with reference to Reynolds number.

2. The Reynolds number for a flow in a channel is 1000. What type of flow is it?
a) Laminar
b) Turbulent
c) Transition
d) Steady
View Answer

Answer: c
Explanation: Reynolds number – 500 to 600 – Laminar flow
Reynolds number – 500 to 2000 – Transition
Reynolds number – > 2000 – Turbulent flow.

3. The ratio of inertia force and gravitational force is called as ______
a) Reynolds number
b) Stokes number
c) Froude’s number
d) Euler’s number
View Answer

Answer: c
Explanation: Froude’s number is the ratio of inertia forces and gravitational forces. Froude’s number is used to classify the flow into critical, sub critical and super critical.
advertisement

4. The Froude’s number for a flow in a channel section is 1. What type of flow is it?
a) Sub Critical
b) Critical
c) Super critical
d) Tranquil
View Answer

Answer: b
Explanation: Froude’s number = 1 – Critical flow
Froude’s number < 1 – Sub Critical flow
Froude’s number > – Super Critical flow.

5. What is the Froude’s number for a channel having mean velocity 4.34 m/s and mean hydraulic depth of 3m?
a) 0.4m
b) 0.6m
c) 0.7m
d) 0.8m
View Answer

Answer: d
Explanation: Froude’s number (Fr) = V/ (gD2)
= 4.34/ (9.81) (32)
= 0.8m.
Free 30-Day Java Certification Bootcamp is Live. Join Now!

6. Calculate the mean hydraulic radius for a channel having 20m2 cross sectional area and 50m of wetted perimeter.
a) 0.4m
b) 0.5m
c) 0.6m
d) 0.7m
View Answer

Answer: a
Explanation: Hydraulic Radius(R) = A/P
= 20/50
= 0.4m.

7. Calculate the mean hydraulic depth of a channel having top width of 7m and cross sectional area of 35m2.
a) 4m
b) 5m
c) 6m
d) 7m
View Answer

Answer: b
Explanation: Hydraulic depth (D) = A/T
= 35/7
= 5m.

8. Estimate the section factor for a channel section having cross sectional area of 40m2 and hydraulic depth of 6m.
a) 94.3
b) 95.6
c) 97.9
d) 100
View Answer

Answer: c
Explanation: Section factor (Z) = A√D
= 40√6
= 97.9.

9. Calculate the Froude’s number for a channel having discharge of 261.03m3/s, cross sectional area of 42m2 and the top width being 6m.
a) 0.65
b) 0.72
c) 0.38
d) 0.75
View Answer

Answer: d
Explanation: Fr= V⁄√gD
V = Q/A
V = 261.03/42 = 6.215 m/s
D = A/T = 42/6 = 7m
Fr = 0.75 (Subcritical).
advertisement

10. Calculate the aspect ratio having channel width of 6m and depth of 8m.
a) 0.75m
b) 1.33m
c) 1.50m
d) 1.68m
View Answer

Answer: b
Explanation: Aspect ratio = Depth / width
= 8/6 = 1.33m.

11. Estimate the type of flow in a channel having cross sectional area of 50m2 and top of the channel is 5m. The mean velocity of flow is 0.1m/s and the absolute viscosity of water is 0.625 N-s/m2.
a) Laminar
b) Turbulent
c) Transition
d) Steady
View Answer

Answer: c
Explanation: Reynolds number (Re)=1000VD/µ
Re = 1000(0.1) (D)/ 0.625
D = A/T = 50/5 = 10 m
Re = 1000(0.1) (10)/ 0.625
= 1600
Transition flow (500 – 2000).

Sanfoundry Global Education & Learning Series – Fluid Mechanics.

To practice all areas of Fluid Mechanics, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
I’m Manish - Founder and CTO at Sanfoundry. I’ve been working in tech for over 25 years, with deep focus on Linux kernel, SAN technologies, Advanced C, Full Stack and Scalable website designs.

You can connect with me on LinkedIn, watch my Youtube Masterclasses, or join my Telegram tech discussions.

If you’re in your 40s–60s and exploring new directions in your career, I also offer mentoring. Learn more here.