Author(s): Heller Valentin; Hager Willi H.; Minor Hans-Erwin
Linked Author(s): Willi H. Hager, Valentin Heller
Keywords: Dynamic pressure; Flow chocking; Jet throw distance; Ski jump; Trajectory bucket
Abstract: Ski jumps in combination with plunge pools are widely used as an energy dissipator downstream of large dams to deflect the discharges from spillways or bottom outlets. They typically consist of an approach chute and a deflector at its end - the flip bucket - to deflect the discharge into the air to a plunge pool. An inappropriate flip bucket design may result in a scour hole too close to the take-off section or valley sides. Despite a number of model studies conducted for specific prototypes, the available general guidelines are currently incomplete. Based on the Froude similitude, 91 experiments with ten different circular-shaped deflectors were conducted, in which the approach flow Froude number, the relative bucket curvature, and the bucket deflection angle were systematically varied. The following summarizes the findings of a hydraulic model study and relates to the maximum dynamic pressure head on the flip bucket, the jet throw distance, and the flow choking conditions. Furthermore, the prototype adaptability of these results is discussed and some of the measurements are compared with existing experiments. The present general guidelines allow for a simplification in designing ski jumps in hydraulic engineering.