Hydraulic Jump Experiment Essay

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Hydraulic Jump Experiment


The Objective of this experiment is to observe the flow patterns and behaviour of the water before after the jump Also to quantify the energy lost due to a hydraulic jump. The observed and theoretical ratios of upstream and downstream depths will be compared, this will show the limitations to purely theoretical analysis.
The experiment showed that a hydraulic jump occurs when when liquid at high velocity discharges into a zone of lower velocity, a rather abrupt rise occurs in the liquid surface. The rapidly flowing liquid is abruptly slowed and increases in height.

The results clearly show the limitations of purely theoretical and purely experimental analysis due to the range of
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Hydraulic jump occurs when the supercritical flow occurs in a channel of which normal flow condition is subcritical.

h2/h1 = ½ (√(1+8F12 )- 1) (4)

The Froude number is calculated using this equation:

F1 = √(q2/gh12) (5)

The hydraulic jump, also known as standing wave, is a rapid transition from supercritical flow to subcritical flow. The transition is generally a turbulent process with a significant energy loss(∆E). that can not be neglected. A hydraulic jump is commonly used to dissipate energy, and reduce the downstream velocity.

To calculate the specific energy at the two separate heights this equation is used:

E = h1 + q2/2gh12 (6)

The total energy loss can be derived as

ΔE = E1 –E2 (7)

To find the height of the jump between the smallest and largest heights:

Δh = h2 – h1 (8)

Finally, the length of the hydraulic jump is given by:

L = 5Δh (9)


2.1 Apparatus

7.8cm Wide open Channel
Depth Gauge measurement devices- Point Gauge and Ruler

2.2 How The Experiment Was Carried Out

Start the pump and turn the flow control valve open.
Allow the
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