单向流作用下多桩承台式基础局部冲刷数值模拟研究

Numerical Investigation on Local Scour of Offshore Multi-pile Foundation under Unidirectional Flow

该文在清水条件下,对海上风电多桩承台式基础的局部冲刷进行了数值研究。结果表明,冲刷过程、深度和流场特征受到桩间距比(G/D=2.0~5.0,G为桩柱中心距,D为桩柱直径)的影响显著。不同G/D下,冲刷坑形态产生较大差异:当G/D=2时,冲刷特性与单桩局部冲刷特性较为相似;当G/D=3时,上游桩后尾涡脱落相互作用,产生顺流向涡结构,显著削弱了下游桩前马蹄涡强度,降低了冲刷速度。;当G/D=4和5时,上游桩后尾涡脱落作用于下游桩,加速下游桩周泥沙起动,在下游产生了更大的冲刷深度。此外,还讨论了不同G/D情况下的尾涡脱落模式及其与泥沙运输的相互作用。

Local scour around offshore wind turbine multi-piles foundation is numerically investigated under clear-water conditions.The characteristics of the scour process,depth,and flow fields are shown to be significantly influenced by the pile gap ratio(G/D=2.0~5.0,G and D are the gap distance between centers of the piles and diameter of the piles,respectively).Under different G/D,the scour hole morphology is quite different.When G/D=2,the characteristic of multi-piles local scour is similar to the single pile.When G/D=3 the front piles vortex shed and interact with each other,creating a streamwise vortex structure that significantly weakens the horseshoe vortex in front of the rear piles and reduces the scouring rate.When G/D=4 and 5,the vortex shedding from the front pile impinges on the upstream face of the rear pile,which significantly mobilizes the sand around the rear pile,and thus leads to a deeper scour hole.In present paper,the vortex shedding patterns and their interaction with the sediment transport in different G/D cases are also discussed.