振荡风电桩基对不同固定冲坑的冲刷影响机理OA

The changes and mechanisms of vortex structures during the development of six fixed scour pits were investigated,and the impact mechanism of pile foundation transverse and longitudinal oscillations on local scour was explored.The results show that,During the development of the erosion pit,a counterclockwise connecting vortex appeared at the bottom,and the horseshoe vortex evolved into two interconnected vortices.At the equilibrium stage,when it reaches its maximum,the range of high average kinetic energy distribution above the bed surface increases.The transverse and longitudinal oscillations increase the shear stress of the bed in the scour pit,and aggravate the local scouring.Longitudinal oscillation causes periodic changes in the topology and connecting vortices of the horseshoe vortex,and the shear stress amplification area gradually increases,with a maximum area of x/D=-0.7～-1.25(D is the diameter of the pile foundation).At T/2(T is the oscillation period),the maximum value of the bed shear stress amplification coefficient is 15.Lateral oscillation creates a complex turbulent zone at the bottom of the scour hole,where the main and small vortices develop into the main horseshoe vortex.The shear stress amplification area is in front of the pile,with x/D=-0.70～-1.25,and the maximum shear stress amplification factor is 4.0～7.8.