New Equations for Rate of Energy Dissipation of a Stepped Spillway with Slope less than Critical and Specific Step Height

Abstract

Stepped spillways disperse energy in floodwater by utilizing their stepping nature. Several researchers investigated the hydraulic and geometric relationships of the stepped spillway with a dam slope above 26.6o, which resulted in energy dissipation. But a few studied stepped spillways with a dam slope of 26.6o with a step height of 0.61 m. This move led to a lack of knowledge and rules for the designers of stepped spillways with slope of 26.6o and a step height of 0.61 m. The authors reviewed the researchers' publications on horizontal stepped spillways with dam slopes of 26.6o with step height of 0.61 m conducted in transition and skimming flows in large-size facilities with phase-detection intrusive probes. They retrieved data sets from them, which they took into account to create two novel equations for energy dissipation in stepped spillways: one for nappe flow and one for skimming flow. The results showed that the measured data sets compared well with the data sets calculated from the two empirical models.