Numerical simulation of two-phase flow on step-pool spillways

The step-pool spillway is inspired by rhythmic sequences of steps and pools in steep mountain streams. By mixing the hydraulic process of stepped spillways and mountainous river step-pool systems, a new kind of stepped spillway, called the step-pool spillway, was designed for a noticeable increase in energy dissipation. The step-pool spillway has increasingly turned into an effective energy dissipator. However, until now, most studies on step-pool spillway overflow have been based on the model test. In this study, the two-phase flow over two types of step-pool spillway was investigated using two-phase schemes (Volume Of Fluid (VOF) and mixture) and various turbulence modeling. Numerical simulation of two-phase flow was carried out on two types of step-pool spillway with various slopes. Comparison of the energy dissipation rates and flow field variables of the present simulation with those of experimental models is presented. Results show that the mixture model with the Reynolds Stress turbulence Model (RSM) is suitable for simulation of two-phase flow over spillways.