Evaluation of Energy Dissipation and Flow Rate of Elliptical-Lopac Gate under Sudden Transition Condition

Lopac gates, with the benefits of easy installation, automation and the ability to pass sediments and floating objects, are among the new structures considered for water level regulation and flow control in the irrigation canals. Converting the shape of the gate from a rectangular one to an elliptical one allows the flow rate to be increased by the same water level. In the present study, the effect of the sudden transition on the discharge and energy dissipation of the elliptical-lopac gate (ELG) in the submerged flow conditions was evaluated in the laboratory. The results showed that the dimensionless discharge and energy dissipation of the ELG with sudden transition to channel width conditions was decreased by 28 to 86% and increased by 11 to 35%, respectively. Finally, the statistical equations were presented to estimate the dimensionless discharge and energy dissipation of ELG by sudden transition under submerged flow conditions with a maximum error of 16%.