Hydraulic Jumps in Adverse-Slope Stilling Basins for Stepped Spillways

Abstract

The performance of flat stilling basins can be inadequate for conditions when the tailwater depth is insufficient for hydraulic jump stabilization. In such cases, adverse-slope stilling basins can be used because they reduce the necessary tailwater depth. Sloped basins combined with smooth chutes have been the subject of many studies. However, limited research has been done for basins with stepped chutes, which are characterized by intensive flow aeration and high energy dissipation. Based on our scale-model experimental measurements of depth, velocity, and air concentration, we present a momentum-based method to characterize such hydraulic jump: the sequent depth ratio, the length of hydraulic jump roller, and energy dissipation effectiveness. The proposed method provides better agreement with experimental data when compared to existing methods and can be used for preliminary design.