Hydraulic performance of elliptical-LOPAC gate under submerged flow conditions

This study intended to investigate the hydraulic performance of the new types of LOPAC gates, namely the elliptical LOPAC (EL) gate, and the rectangular LOPAC (RL) gate for irrigation canals. To that end, 90 experiments were carried out at three different flow discharges (25, 35, and 45 l/s), three different submergence ratios (y(2)/y(1) = 0.7, 0.8, and 0.9) and five different gate opening angles (35, 40, 45, 50, and 52.5?). In the EL gate, as the submergence ratio decreased by 20%, the maximum increase in Cd for the discharges of 25, 35, 45 l/s at 52.5 degrees of gate opening angles happened in the order of 0.426, 0.475, and 0.506, respectively. Moreover, the maximum decrease ratios in Delta E/E-1 followed by 20% increase in the submergence ratio for the same discharges at 35 degrees of gate opening angles were 0.195, 0.1944, and 0.1922 respectively. Finally, the empirical rating curve and equations were proposed to predict C-d and Delta E/E-1 for both the EL and RL gate models. For the EL gate, the RMSE ratios for the proposed C-d and Delta E/E-1 equations were obtained 0.0027 and 0.0021 respectively. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Faculty of Engineering, Ain Shams University.