Three-Dimensional Numerical Model with Free Water Surface and Mesh Deformation for Local Sediment Scour

摘要

A numerical model for local sediment scour with free surface and automatic mesh deformation is constructed and numerical results are compared with experimental results. For the turbulence closure, the two equation k-ε model is used. Two interfaces (water and air, water and sediment) in the domain are captured with different approaches. The free surface of the flow is simulated with the volume of fluid (VOF) scheme, which is an Eulerian approach. A new method for the VOF scheme is proposed to reduce the computational time while retaining relative accuracy. The behavior of the water-sediment interface (bed) is captured with a moving-mesh method, which is a Lagrangian approach. The flow field is coupled with sediment transport (both bed load and suspended load) using a quasi-steady approach. Good results have been obtained using the current model. The flow field is similar to the one observed in experiments. Scour patterns are similar to the experimental data as well. Large computational times are needed for morphological simulation and parallel computation is used to accelerate this process. The results obtained from the model are promising.