3D numerical simulation of the flushing process in the Angostura reservoir

To predict the magnitude of flushed out sediments and to predict where in the reservoir erosion takes place is still a challenge in engineering. Physical models are often used to get knowledge of the success of an upcoming flushing. In this study a numerical program is presented as an alternative. The used CFD code solves the RANS-equations in three dimensions. The turbulence is modelled by the k-epsilon model and the pressure by using the SIMPLE method. An unstructured and non-orthogonal grid is used in the model. The suspended sediment transport is computed by solving the convection-diffusion equation and the bed-load transport by an empirical formula. The model is adjusted with measured sediment sizes of the bed material, discharge rates and water levels during the flushing. Results of the location and the amount of the erosion are presented in this study, which show good agreement with the measurements.