Numerical Investigations Of The Horse-shoe Vertex With Different Pier Section Shapes

The horse-shoe vortex(HV)is responsible for local bed scouring.In order to suppress the local bed scouring induced by HV,a serious of numerical simulations were carried out to investigate the effect of the pier section shape on the intensity of the HV.The present free surface numerical model is developed based on finite volume method(FVM)with unstructured grids.The turbulent flow is modeled using Menter's two equations SST k-?turbulent model.Firstly,the model was validated by experimental measurement of flow around a vertical cylinder with Re_D=39000.The good agreements with pressure coefficient,velocity and bed shear stress around the pier verified the present model.Furtherly,a serious of study cases were performed to investigate the effect of pier section shape on the HV at the basement of the pier,including the position,the strength of HV,the water level,the bed pressure coefficient distribution around the pier and the distribution of bed shear stress amplification.The present work focused on analyzing the influence of the pier shape on the HV and looking for feasible pier shape to suppress the intensity of the HV.The results show that the positon and the intensity of HV differ with different pier shape.Besides,the water level upstream of the pier leading edge and the sharpness of the leading edge both are responsible for the HV.