Experimental study on the hydraulic performance of trapezoidal planform compound labyrinth weir

Labyrinth weir is considered one of the most efficient solutions to regulate upstream elevations of water and hence increasing in flow capacity through increasing the crest length without changing the existing width of the structure. The trapezoidal planform of Labyrinth Weir is common shape used to regulate the water flow. The major aim of the present study is to investigate the hydraulic performance of a newly developed geometry of compound labyrinth weir under free flow conditions in the rectangular laboratory flume. In this study, 10 lab scale models are fabricated to investigate major design parameters which affect the weir efficiency for sidewall angle, weir orientation and weir height. The compound discharge coefficient for flow through holes and over trapezoidal labyrinth weir will be quantified from the test measurements. The curves were found from experimental data that show the relationship between the discharge coefficient and dimensionless term HT/P of one cycle compound labyrinth weir. The result shows that reducing the weir height result in increasing the coefficient of discharge (Cd) values for a given total head over weir height (Ht/P). Test results confirmed that the value of Cdc does not change significantly when comparison orientation of labyrinth weir.