Stepped spillway is hydraulic structure designed to dissipate considerable kinetic energy because it's characterised by the large value of the surface roughness. On stepped chutes with skimming flow regime, the flow is highly aerated which can reduce the risk of cavitation. The air entrainment starts where the boundary layer attains the free surface of flow; this point is called “point of inception”. In the present numerical study, the Reynolds-Averaged Navier–Stokes equations are coupled with k −ε turbulence standard model to simulate the water flow over stepped spillway by using the software Ansys Fluent. Volume of fluid (VOF) model is used as a tool to track the free surface flow. This research aims to find new formulas for describe the variation of water depth and the positions of the inception point. In addition, to study the characteristics of flow over stepped spillways. The found numerical results agree well with experimental results.


Ansys Fluent, VOF Model, Air entrainment, Stepped Spillway, Standard k– ε Model,

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