Numerical analysis of flow over stepped spillways

Stepped spillways dissipate highly energy of the flow and decrease the sizes of stilling basin. Popularity of stepped spillways increase widely with using the roller compacted concrete dams. These type spillways have energy dissipation capacity %70-80 ratio more than classical spillways.In the recent times computational methods were developed and thus using of advanced numerical models became widespread. Studies related to stepped spillways exist in the literature. But, studies about the numerical analysis of the stepped spillways are less. Moreover, the stepped spillways with end sill don?t exist in the literature.In this study, energy dissipation ratio of both stepped spillways with end sill and stepped spillways without end sill were examined. For stepped spillways, numerical analyses were made for different slope angles and ratios of h/l. For stepped spillways with end sill, numerical analyses were conducted for different slope angles, different ratios of h/l and different types of sill. Computational Fluid Dynamics (CFD) was used as a method of numerical study. Analyses were made using of the Fluent 6.2 software. Results obtained from numerical analyses were compared those of with equation in the literature and the results were interpreted.It is concluded that, results of numerical analyses are very close to experiment results. It is demonstrated that, numerical analysis results of the stepped spillways are reliable. At the slope angle with 30°, Type 4 has the most energy dissipation ratio. In addition to this, at the slope angle with 50°, the stepped spillway without end sill has the most energy dissipation ratio.