Energy dissipation and flow characteristics of baffles and sills on stepped spillways

Abstract

In this study, a two-dimensional physical model was used to evaluate the effectiveness of adding baffles and sills at step edges or of shifting them from step edges of a 1V:1H sloping, short, sharp- or round-crested stepped spillway with an ogee inlet. A comparison between different configurations of baffles and sills was carried out with respect to the energy dissipation and the flow characteristics. The baffle-shifted round-crested spillway gives the smallest discharge required for the onset of a skimming flow among all other configurations. The baffle-edged chute dissipates more energy than the sill-edged spillway. Shifting baffles or sills from the sharp edges decreases the energy dissipation. Shifting baffles or sills from the round-crested spillway increases the energy dissipation in the range of the discharges studied. Empirical equations for energy dissipation are introduced for practical application of spillways of comparable similar conditions.