Author(s): Hubert Chanson; Stefan Felder
Linked Author(s): Stefan Felder, Hubert Chanson
Keywords: Stepped spillways; Overflow stepped weirs; Turbulent kinetic energy dissipation; Embankment structures; Masonry spillways; Air-water flows; Residual energy
Abstract: Stepped spillways are designed to increase the rate of energy dissipation on the chute reducing the size of a downstream energy dissipator. The prediction of the turbulent dissipation above the steps constitutes a critical part of the design process, especially at large discharges per unit width corresponding to the skimming flow regime. Herein new measurements were conducted in a large facility with a channel slope of 26.6oand step heights of 0.10 m. The experiments were performed with large discharges corresponding to Reynolds numbers ranging from 5×10 4 to 1×10 6. The waters were highly turbulent and they dissipated a major proportion of the flow kinetic energy. Taking into account the free-surface aeration, the present results were compared with recent results on 15.9oand21.8oslopes; the range of slopes (1V: 3.5H to 1V: 2H) was typical of embankment slopes and older spillway designs. The comparative results yielded some simple design guidelines applicable to masonry stepped spillways, embankment dam stepped chutes and overflow stepped weirs.
Year: 2010