3D NUMERICAL SIMULATION OF LOCAL SCOURING DOWNSTREAM OF A GROUNDSILL

Abstract

 Local scouring that occurs downstream of a groundsill may affect the stability of the structure. Therefore, prediction of flows and local scouring downstream of such a structure is of great importance in river engineering. In this study, numerical simulation of local scouring downstream of a groundsill is carried out by using a three-dimensional flow model that can predict simultaneously both surface and seepage flows in a generalized curvilinear coordinate system and an equilibrium sediment model. Although the velocity distribution near the riverbed and the location of the dunes behind the scour during the submerged jet is not simulated well, it is shown that the model reproduces the longitudinal distribution of riverbed and water level, vertical velocity distribution during the submerged jet and the backfilling process, and the temporal variation of the maximum scour depth reasonably. In addition, the influence of seepage flows on local scouring is also discussed.