3D numerical simulation of free surface flows over hydraulic structures in natural channels and rivers

In this paper, a three-dimensional numerical model is developed, in which an Euler implicit method for the temporal discretization and the Finite Volume Method for the spatial discretization are applied to solve the Reynolds-averaged Navier-Stokes (RANS) equations for free surface flows over hydraulic structures in natural channels and rivers. At the free surface two different methods, the front-tracking and the front-capturing, are applied to calculate free surface profiles. The model has been validated against typical benchmarking experiments, and applied to a number of practical applications for natural rivers in Germany. Due to the limitation of the observation data in some application cases, in order to verify our numerical model, we besides have modified and applied the well-known open source CFD toolbox OpenFOAM to the same applications, then compared the results obtained from the OpenFOAM with our model results.