Question

If the Froude number of a hydraulic jump in a horizontal rectangular channel is 4.2, then the jump can be classified as:
1.  Undular jump
2. Oscillating jump
3. Weak jump
4. Steady jump

Answer 1

Correct Answer - Option 2 : Oscillating jump

Explanation

Based on the severity of jump and Froude number hydraulic jump is classified as follows:

1. Undular Jump: Froude number for this flow is between 1 to 1.7. Such a type of jump is weak in nature and no significant water level rise is observed.

2. Weak Jump: Froude number for this flow is between 1.7 to 2.5. These jumps are also natural jump and energy loss in these jumps is also less.

3. Oscillating Jump: Froude number for this flow is between 2.5 to 4.5. It is oscillating in nature.

So, Given F_r = 4.2 lies between 2.5 - 4.5. The jump is classified as Oscillating Jump

4. Steady Jump: Froude number for this flow is between 4.5 to 9.

5. Strong Jump: Froude number for this flow is greater than 9.0. Such jump is generally engineered for heavy losses.