# Fluid Mechanics Questions and Answers – Hydraulic Jump

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This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Hydraulic Jump”.

1. Hydraulic jump is observed in _______
a) Closed channel flow
b) Open channel flow
c) Flow changes
d) Volumetric changes

Explanation: Hydraulic pump is a phenomenon in science that deals with hydraulics. It is observed in an open channel flow. Some of the examples of open channel flows are rivers and spillways.

2. Hydraulic jump depends upon
a) Temperature
b) Pressure
c) Initial fluid speed
d) Volumetric changes

Explanation: Hydraulic pump is a phenomenon in science that deals with hydraulics. It is observed in an open channel flow. It depends on the initial speed of the fluid. Thus, option Initial fluid speed is the correct answer.

3. In which case is the hydraulic jump not possible?
a) Initial speed > critical speed
b) Initial speed < critical speed
c) Initial speed = critical speed
d) Independent

Explanation: Hydraulic jump is not possible when the initial speed is less than the critical speed. There is a transition that is created during the change. The transition appears as an undulating wave. With the increase in the initial flow, the transition becomes abrupt.

4. Open channel flow takes place _______
a) On a free surface
b) In the pipe
c) Within a cylindrical depth
d) In a pump

Explanation: Open channel flow is a flow that deals with hydraulics in fluid mechanics. It is a type of liquid flow that flows through a free surface. This free surface is called as a channel. And since the channel is free, it is called as an open channel flow.

5. When the hydraulic jump is in a moving form it is called _________
a) Negative surge
b) Positive surge
c) Turbulent surge
d) Accelerated surge

Explanation: When the hydraulic jump is dynamic or in a moving form it is called as positive surge. Hydraulic jump can be stationery or dynamic. Hydraulic jump can be described using the same analytical approaches.

6. Fluid speed before the hydraulic jump is ________
a) Critical
b) Supercritical
c) Subcritical
d) Dynamic

Explanation: Fluid speed before the hydraulic jump is supercritical. It is said to be supercritical because it is faster than the wave speed. It is also called as shooting speed or superundal.

7. Fluid height before the hydraulic jump is ________
a) Normal
b) Low
c) High
d) Zero

Explanation: Hydraulic jump is not possible when the initial speed is less than the critical speed. There is a transition that is created during the change. The transition appears as an undulating wave. Fluid height before the hydraulic jump is low.

8. Fluid height after the hydraulic jump is ________
a) Normal
b) Low
c) High
d) Zero

Explanation: Hydraulic jump is not possible when the initial speed is less than the critical speed. There is a transition that is created during the change. The transition appears as an undulating wave. Fluid height after the hydraulic jump is high.

9. Fluid flow before the hydraulic jump is ______
a) Normal
b) Rough
c) Smooth
d) Zero

Explanation: Hydraulic jump is not possible when the initial speed is less than the critical speed. There is a transition that is created during the change. Fluid flow before the hydraulic jump is typically smooth turbulent flow.

10. Fluid flow after the hydraulic jump is ______
a) Normal
b) Rough
c) Smooth
d) Zero

Explanation: Hydraulic jump is not possible when the initial speed is less than the critical speed. There is a transition that is created during the change. Fluid flow after the hydraulic jump is typically rough and choppy turbulent flow.

11. During a subcritical flow, what is the value of Froude’s number?
a) Zero
b) Greater than one
c) Less than one
d) Not defined

Explanation: Subcritical depth occurs when actual water depth is greater than the critical depth. It is dominated by gravitational forces and behaves in a slow and stable way. The Froude’s number is less than one during a subcritical flow.

12. Which hydraulic jump occurs in our sink?
a) Inertial forces hydraulic jump
b) Shallow fluid hydraulic jump
c) Critical depth jump

Explanation: Shallow fluid hydraulic jump takes place during a hydraulic jump that is created in our sink. It will undergo a smooth flow during the hydraulic jump as the flow is shallow.

Sanfoundry Global Education & Learning Series – Fluid Mechanics.

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