Ski Jump Hydraulics

Abstract

Ski jumps are a major element of each dam spillway because these are the only structures able to accomplish satisfactory energy dissipation for takeoff velocities in excess of some 20 m / s. This research aims to add to several hydraulic problems with ski jumps that have not yet been systematically solved so far. Based on an experimental campaign, the following problems were addressed: ~1! pressure head maximum and pressure distribution along a circular-shaped flip bucket; ~2! takeoff characteristics for a certain bucket deflection and a relative bucket curvature including the jet trajectories of both the lower and the upper nappes; ~3! impact characteristics in a prismatic tailwater channel with details of shock wave formation and height of recirculation depth; ~4! energy dissipation across the ski jump, from the upstream channel to downstream of jet impact; and ~5! choking flow conditions by the flip bucket. These results demonstrated the significant effect of the approach Froude number, the relative bucket curvature and the bucket angle. The results allow immediate application to the design of ski jumps in hydraulic engineering.