Application of a nested grid hydrodynamic model to discharge pattern simulation overhaul conditions of Sanhe Sluice

When the Sanhe Sluice's overhaul project was conducted,63 half-open gates were operated for the purpose of simultaneously discharging water and replacing hoists.A 2D-3D coupled model was put forward and the local nested grid method was employed to simulate the flow patterns of the Sanhe Sluice.The results show the following:(a) In this overhaul situation,there is a wide range of recirculation zones in both the upstream and downstream reaches,and the discharge per unit width increases locally.(b) The Kuaihuo Ridge upstream has a significant influence on the inflow pattern.(c) The flow deflection is more severe with half-open gates than with fully opened gates,and the maximum average deflection angle is 27.35° for the northern discharging case.Based on the numerical simulation results,we make some recommendations for improving the flow pattern,which can provide references for operation and management of the Sanhe Sluice in the overhaul project.