ABSTRACT
This paper provides some measurements carried out to identify the air inception location of skimming flow in a large model of a stepped spillway for two slopes. A review of investigations on chute and stepped spillways is also presented. Parameters that influence the air inception have been identified. It was found that the enhancement of the growth of the boundary layer and the deflection of the internal flow by steps causes an early inception of air entrainment. The location of the inception section moves downstream as the discharge increases. For a specific step height, the inception section moves downstream as the discharge increases. Observation revealed that the distance of the inception point from the crest is shorter for stepped spillways as compared to chute spillways. An empirical formula for the distance of the air inception section from the crest is developed to fit the experimental data.
