Experimental and numerical simulation of flow over stepped spillways

Stepped spillways are used in the construction of dams, river engineering and soil conservation projects. Energy dissipation in this structure due to the presence of several steps is high, so the construction costs for stilling basin are reduced. The numerical models are new method for flow analysis. This study investigates the flow on the stepped spillway and calculates energy loss caused by it. Also in this study, fluctuation of velocity vectors, shear stress and pressure during the flow on each step is compared. For this purpose, a physical model of the stepped spillway was built with slope at a ratio of 2:1 (horizontal to vertical) and experiments were performed with ten different flow rates. The numerical simulations also were performed under the same conditions using FLUENT software and RNG k-epsilon turbulence model. Finally, the results of the numerical model were compared with experimental data. The results indicate that numerical model is in reasonable consistency with the physical model and it can be used in anticipation complex rotational flows in the stepped spillway.