# Hydraulic Jump

Topics: Fluid dynamics, Froude number, Kinetic energy Pages: 8 (1240 words) Published: October 5, 2011
Laboratory Report for Sluice Gate
and Hydraulic Jump

Introduction.

In this lab exercise we were supposed to analyse the Hydraulic jump through the Sluice gate, and to discuss about the energy displacement through that process. Hydraulic jump is known as the change flow which changes from the supercritical flow to the sub-critical flow, this change occurs due to the loss turbulence in an open tunnel. In basic terms this happens when there is a sudden rise in the water levels, due to the change that takes places when the velocity deceases. In reality different types of hydraulics jumps are made to match the human needs. The gate that controls the amount of water flowing through an open channel is known as the Sluice Gate. This gate system is used to avoid problems that occurs in open channels such as erosion of soil due to the high velocity flows. In modern day these gates are used in flooding areas in place of barriers, dams and in coastal areas in case of tidal wave flooding.

Apparatus.
Open channel,
Meter ruler,
Vernier calliper,
Sluice gate,
Centrifugal pump,
Electro magnetic flow meter.

Procedure.
First the dimations of the Channel was measured using the meter ruler. After this the motor was turned ON.
The flow of the water level was controled by the sluice gate which could be adjusted verticaly. The flow of the channel at that ponit was meaured using the electro magnatic meter. The horizontal measurnent of the strem was noted as well.

At four different points the depth of the water was meaured, which was at up stream plus the down stream of the channel, and at the start plus the end of the hydralic jump. All these measurements were taken using the vernier calliper. All the above readings were taken when the vernier was set to zero.

Flow rate= 133
Width of the channel= 150 mm

Section

Location
Distance (mm)
Depth (mm)
1

Up stream of the sluice gate
320
274.6
2

Down stream of the sluice gate
570
9.6
3

Start of the hydraulic jump
1059
14.0
4

Start of the hydraulic jump
1320
71.8

Calculations.
Flow (Q) = 104 / (1000 x 60)
= 1.734 m

Velocity at section 1V =
= 1.734 m
(274.6)x(150)m2
= 0.042 m/s

Velocity at section 2V = 1.734 m
(9.6)x(150)m2
= 1.204 m/s

Velocity at section 3V = 1.734 m
(14)x(150)m2
= 0.826 m/s

Velocity at section 4V = 1.734 m
(71.8)x(150)m2
= 0.161 m/s

Froude number Calculations.
F =
Rectangular channel V =
from bouth equations you get
F =
Froude number for section 1=
= 0.042 m/s
√(9.81x 0.2746)
= 0.026

Froude number for section 2= 1.204 m/s
√(9.81x 0.0096)
= 3.923

Froude number for section 3= 0.826 m/s
√(9.81x 0.014)
= 2.229

Froude number for section 4= 0.161 m/s√(9.81x 0.0718)
= 0.192

Specific Energy.
E = + y

Specific energy at section 1= 0.042² m/s + 0.2746
2 x 9.81 ms²

= 0.090 + 0.2746
= 0.3646m

Specific energy at section 2= 1.204 ² m/s + 0.0096
2 x 9.81 ms²

= 0.074 + 0.0096
= 0.0836m

Specific energy at section 3= 0.826 ² m/s + 0.014
2 x 9.81 ms²

= 0.035 + 0.014
= 0.049m

Specific energy at section 4= 0.161 ² m/s + 0.0718
2 x 9.81 ms²

= 0.0013 + 0.0718
= 0.0731m

Section

Location
Distance (mm)
Depth
(mm)
Velocity (m/s)
Froude number
Specific energy (m)
1

Up stream of the sluice gate

320

274.6

0.042

0.026

0.3646
2

Down stream of the sluice gate

570

9.6

1.204

3.923

0.0836
3

Start of the hydraulic jump

1059

14.0

0.826

2.229

0.049
4...