Residual Energy on Ski-Jump-Step and Stepped Spillways with Various Step Configurations

Abstract

To better understand the effects of optimized step configurations and preaeration structure of a ski-jump-step spillway on the residual energy of skimming flows, skimming flow experiments were conducted on both ski-jump-step and stepped spillway models. Horizontal, inclined, and pooled steps were tested on each. The results show a significant reduction in residual energy of the ski-jump-step spillway compared to that of the stepped spillway. Use of the inclined and pooled steps on the ski-jump-step spillway aids in further reducing the residual energy, particularly under large unit discharges. The authors introduce a new geometrical parameter of steps, the area of cavity, and find that it is negatively correlated with the residual energy. A unifying correlation showing the relationship among residual energy, unit discharge, slope of step, and area of cavity is established for evaluating the residual energy of skimming flows on ski-jump-step and stepped spillways with various step configurations.