Experimental and Numerical Investigations of Hydraulics in Water Intake with Stop-Log Gate

Abstract

A stop-log gate, installed in water intake of hydropower project, has become an effective facility in achieving selective withdrawal and temperature control for the sake of benefiting downstream ecosystems. Hence, it is of great importance to comprehensively explore the water intake hydraulics with the gate, not limited to some specific case studies. This study deals, through laboratory experiments and numerical simulations, with flow features of such a gate-functioned intake. The physical model test is used to validate the numerical simulation. Subsequently, a series of numerical cases considering different hydraulic and geometric conditions are performed to help look into the behaviors. Particular attention is paid to the flow regimes, head loss and flow velocity distributions. The results showcase the effect of the gate on the intake flow regime, and in terms of head loss and flow velocity distribution, the influences of the upstream water head, intake chamber width and withdrawal depth are revealed in detail. An empirical expression, with regard to the coefficient of head loss, is derived and validated by data from the available literature. Moreover, it is found that the maximum velocity at trash rack section is dependent exclusively on the relative withdrawal depth and always occurs at a certain height range above the gate. These results may provide a meaningful reference for the research of water intake with similar situations.