砂土地基中海上风电四桶吸力基础冲刷特性研究OA

To address the complex local scour behavior of four-bucket suction foundations for offshore wind turbines induced by group-pile effects,a series of large-scale physical model tests were conducted in a wave-current flume at a geometric scale of 1:50.The effects of incoming flow direction and flow intensity on scour morphology and scour evolution around the four-bucket foundation were systematically investigated under unidirectional current and wave-current coupling conditions.The results indicate that local scour around the four-bucket foundation is dominated by independent scour pits forming around individual buckets;however,the spatial distribution of scour intensity is markedly non-uniform,primarily governed by the modification of the near-bed flow field caused by hydrodynamic interference among the buckets.Under oblique inflow conditions,increasing the angle of incidence significantly reduces the geometric projection spacing of the bucket group perpendicular to the incoming flow,leading to contraction of the effective flow passage between buckets and pronounced local flow acceleration.Consequently,scour depth around the side buckets is substantially amplified,with the 45° inflow condition identified as the governing case for scour protection design.Under axial inflow conditions,a pronounced hydrodynamic shielding effect is observed,whereby the front-row buckets dissipate incoming flow energy and reduce the effective flow velocity acting on the rear-row buckets,resulting in a reduction in scour depth of approximately 10％-20％compared with the front-row buckets.Moreover,this shielding effect progressively weakens with increasing Froude number,indicating that the protective influence of the front-row buckets diminishes under high-flow-intensity conditions.In addition,under wave-current coupling with a low Keulegan-Carpenter number,wave-induced disturbances disrupt the stable vortex system and promote sediment backfilling,leading to a shallower equilibrium scour depth compared with the corresponding pure current condition.This process exhibits a nonlinear scour evolution characterized by rapid initial development followed by a reduced final scour depth.The findings of this study provide a scientific basis for scour risk assessment and the design of scour protection measures for multi-bucket suction foundations.