Ski-jump characteristics of ski-jump stepped spillways

To prevent the semi-submerged jet in ski-jump stepped spillways, which leads to abnormal pressure distributions, severe water wing phenomena and structural vibrations in the upstream step section, a combination of physical model tests and theoretical analysis was used, and three types of test models were designed to study the influence of installing ventilation shafts and extending the inlet horizontal section on the flow pattern and hydraulic characteristics of the ski-jump section. The results show that installing ventilation shafts and extending the inlet horizontal section can significantly improve the ski-jump flow pattern, effectively mitigate the water wing phenomenon, and successfully eliminate adverse hydraulic conditions such as negative pressure. The maximum operating discharge for the ski-jump stepped spillway and the minimum length of the aeration basin were determined, providing a reference for the structural design and operation of ski-jump stepped spillways.