Numerical investigation of flow characteristics over stepped spillways

Computational Fluid Dynamics (CFD) is one of the actual ways to study different hydraulic problems because it saves cost and getting reliable results in record time. It is used to solve different fluid flow problems such as flow velocity, temperature, density and chemical concentrations for any area in which there is flow. This study investigates the simulation of the influence of slope changes on flow characteristics such as air entrainment, velocity distribution and dynamic pressures distribution over the stepped spillway. The results from the numerical model were compared with the experimental study done by Mirza (2016). The experimental works were assembled at the Laboratory of Hydraulic Constructions (LCH) of the Ecole Polytechnique Fédérale de Lausanne (EPFL) Switzerland by Mirza (2016). Air concentration and velocity distribution profiles were measured perpendicular to the pseudo-bottom up to the water surface while the dynamic pressures calculated on the horizontal step face of the spillway. The two models of the stepped spillway with different discharge for each model was simulated. Since the actual flow is turbulent in the experimental model, the Renormalized Group (RNG) turbulence model was chosen in the numerical modeling. A good agreement was achieved between the numerical results and the observed data.