CFD analysis on the performance of an overturnable water gate for reservoir spillway

The automatic overturnable water gate for the spillway of a reservoir is one method of increasing the water storing capability of small agricultural reservoirs. Overturning and restoring of the water gate are the key points of its design, but it has been very difficult to analyze their effects through field measurements because of the difficulties in designing artificial experimental conditions. Accordingly, a 2-D CFD (computational fluid dynamics) numerical simulation was designed to overcome the weaknesses of field experiments as well as compare their efficiencies under various conditions. The water-air interface was determined by the VOF method, and the motion of the gate was modeled using the dynamic mesh method and the user defined functions (UDF). The accuracy of the CFD model was examined using the hydrostatic estimation data and the results were found reasonable. The restoration of the gate, as the critical problem, was significantly affected by the water's dynamic force, and the CFD analysis suggested some remedies to improve the gate operation. The study also indicated that CFD simulation could be effectively used to design and evaluate various hydraulic structures.