Numerical Study of Flow on Stepped Spillway and Its Comparison with Experimental Results

Stepped spillways are frequently used in the structure of dams, river engineering and soil conservation. Energy dissipation on this structure due to the presence of several steps is high, so causes reduction in construction costs of stilling basin. On the other hand, nowadays numerical models are new methods for flow analysis. The purpose of this study was numerical investigation of the flow on the stepped spillway and calculation of the energy loss caused by it. Also, the fluctuations of velocity vectors, shear stress and pressure during the flow on the each step were compared. For this purpose, a physical model of the stepped spillway was built with a slope ratio of 2:1 (horizontal: vertical), and the experiments were performed with 10 different flow rates. The numerical simulations also performed under the same conditions by using FLUENT software and RNG k-ε turbulence model. Finally, the results of the numerical model were compared with experimental data. The results indicated that the numerical model with an error of about 3% had a good agreement with the physical model, so it could be trusted for anticipating complex rotational flows on the stepped spillways.