Two-Dimensional Modeling of the Two-Phase Flow over Stepped Spillways

Different measures may be taken into account in order to reduce the destructive effects of flow over spillways، one of which is the application of stepped spillways in an attempt to dissipate the flow energy. This method also influences the economic justification of the project and reduces the costs. The present study simulated the free surface and the two-phase flow patterns over the stepped spillway employing the Fluent software، and adopting the mixture model as well as the standard K – ε turbulence model. The numerical model verification was conducted utilizing the data of air concentration distribution in water، and the velocity at different discharge rates collected in experiments performed by Chamani utilizing a physical model at Hydraulic Laboratory conducted at the University of Alberta. The numerical simulation results and experimental data were in good agreement. Concentration profiles led to a stair like distribution of the concentration، and the discharge effects on the shapes of velocity profiles were comparable. The results showed that as the inlet discharge increased، velocity profiles widened and spread more، and flow height and maximum flow velocity rose، which in turn reduced the flow dissipation