Parametric study on the influence of jet-like inflows and outflows on fine sediment settling

This paper focuses on the dynamics of fine sediments in reservoirs exposed to hydropower cascade or pumped-storage operations. The aim is at analysing the influence of parameters such as the flow inlet and flow outlet relative position, the jet hydrodynamics, and the concentration of fine sediments on the settling process. Based on multiphase-threedimensional simulations, the results reveal a good correlation between the patterns of sediment deposition and turbulent dissipation rate. Numerical simulations were performed on the Computational Fluid Dynamic (CFD) software ANSYSCFX. These simulations cover 4 geometries, 2 jet velocities and three concentrations of sediments in the jet inflow. The results show that the deposition of fine sediment correlates with the turbulent dissipation rate. Indeed, the deposition is comparatively high in zones with high turbulent dissipation rate, such as in the vicinity of the jet-like inlet and outlet; whereas in zones with low turbulent dissipation rate the deposition is comparatively low.