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Abstract

Broad crested weirs are hydraulic structures that are commonly used in hydraulic engineering to measure the discharge of rivers and also control the flow discharge. They can also generate hydraulic jumps which are used for a variety of purposes but most namely is energy dissipation, mixing of chemicals, irrigation purposes and removal of air entrainment.
This project focuses on the effect of weir length and height on predicating the length and estimating the location of the jump. To investigate this, current theoretical approaches in regards to predicting the length and the location of the jump were sourced and alongside experimental laboratory data they were compared and contrasted. Regression model equations were produced to provide legitimacy to the findings. To highlight the most effective and efficient model in regards to the geometric profile to dissipate the jump’s energy.
From the analysis it was demonstrated that the only reasonable geometric profile to predict the length of the jump was Model G4 with a length of 0.35m, width of 0.3m, and a height of 0.25m. For further analysis, error variables were calculated to identify the margin of errors. Observing the location of the jump saw that numerous regression models produced that did not represent the experimental data well.
The energy dissipation saw a reduction in energy between 9.85%-29.15% in terms of the influence of weir length. On the other hand, the height of the weir produced a range of dissipation between 36.1%-50.84%. In summary, this project would profit from a broad and steady range of Froude numbers to produce many other types of jumps.

Course: Civil Engineering - MSc - C0618

Date Deposited: 2022-03-04

URI/permalink: https://library.port.ac.uk/dissert/dis13858.html