SIMULATION OF HIGH VELOCITY FLOWS IN CHUTES WITH NONPARALLEL SIDEWALLS USING UPWIND and CENTRAL OVERLAPPING FINITE VOLUMES

This paper presents the comparison between the numerical results of central and upwind results of a computational model which efficiently simulate super-critical free surface flow in channels with nonparallel side walls. This model computes water depth and velocity components in horizontal plane using shallow water continuity and equations motion in horizontal plane. This model evaluates twodimensional velocity patterns and shockwaves. The governing equations are discretized utilizing over lapping cell vertex finite volume method on triangular unstructured meshes. The numerical oscillations of explicit solution procedure are damped out using either artificial viscosity scheme or upwind averaging fluxes at control volume boundary edges. The algorithm of evaluation of the fluxes at edges and artificial dissipation terms at nodes is adopted for unstructured meshes. Using both techniques, no additional dissipation is introduced to the computed flow and shockwaves are simulated accurately. The efficiency of the model is improved using edge base data structure for addressing unstructured mesh details. The accuracy of results is assessd by simulating super-critical flow in two chute canal with expanded and contracted walls and using comparison of between the computation results with the reported experimental measurements.