Author(s): Chaewoong Ban, Sung-Uk Choi
Keywords: Surface jet; Large eddy simulation; Mean flows; Turbulent statistics; Submerged weir;
Abstract: Local scour downstream of a weir is a common problem that can result in serious damages to the weir itself. This study presents results from large eddy simulations (LESs) for surface jets over a submerged weir. Turbulent surface jets were computed over the flat and deformed beds due to scour for the same approach flow. The mean flow and turbulent statistics are presented for both flat and deformed bed conditions. Turbulent flows with the scour hole show that the reattachment region starting from the edge of the weir is located further downstream compared to the flows without scour. Furthermore, due to the presence of the scour hole, both average kinetic energy (AKE) and turbulent kinetic energy (TKE) increases and vertical gradient of the AKE become steeper compared to the flat bed case. This demonstrates that the capability of energy transfers from the AKE to the TKE increases by forming the scour hole on the flat bed.