Which of the following assumptions are made in the analysis of hydraulic jump?
- ALoss of head due to friction at the walls and channel bed is negligible.
- BThe Flow is uniform, and the pressure distribution is hydrostatic before and after the jump.
- CThe channel is horizontal, or it has a very small slope.
- DAll of the aboveCorrect
Solution
Concept
Assumptions made in hydraulic jump analysis
Formula
NONE
Step-by-step solution
1. Hydraulic jump analysis applies the momentum equation across a short channel reach. 2. Standard assumptions include negligible friction losses along channel walls and bed due to the short length of the jump. 3. Additional assumptions require uniform flow with hydrostatic pressure distribution before and after the jump, and a horizontal or near-horizontal bed slope. Answer: D
Explanation
The analysis of a hydraulic jump utilizes the momentum principle across a short channel reach. It assumes that friction losses against the bed and walls are negligible because the jump occurs rapidly over a short distance. Additionally, it assumes hydrostatic pressure distribution before and after the jump, along with a horizontal or low-sloped channel bed, making all listed statements correct.
Why the other options are wrong
A) Option A is only one of several standard assumptions made in hydraulic jump analysis. B) Option B is only one of several standard assumptions made in hydraulic jump analysis. C) Option C is only one of several standard assumptions made in hydraulic jump analysis.
Shortcut
Hydraulic jump theory assumes zero friction, hydrostatic pressure, and a flat bed (All of the above).
Common mistake
Selecting only a single familiar assumption rather than recognizing that all given options are valid assumptions.
Correct answer: D) All of the above