Studying the effect of shape changes in plan of labyrinth weir on increasing flow discharge coefficient using Flow-3D numerical model

Engineers are looking for solutions for flood control and increasing discharge capacity of canals and rivers. Application of labyrinth weir is suggested as a solution for increasing discharge capacity. In this research, labyrinth weir with sidewall angle that was equal to 6°, was simulated through Flow-3D model using experimental results of previous researchers. After validation, the changes of discharge coefficient of weir with angles of 45° and 85° and apex shapes of triangular and half circular shapes were analyzed. Based on the results, discharge coefficients of labyrinth weir with angles of 85° and 45° were on average 2.28 and 1.24 times greater than discharge coefficient of labyrinth weir with angle of 6°, respectively. Also, discharge coefficient of weir with triangular and half circular apex shapes has an increase of 50.29 and 4.15% in comparison with linear apex. Finally, an equation was proposed for prediction the discharge coefficient of labyrinth weir that is able to estimate the discharge coefficient with an acceptable level of accuracy.