The flow field near a spur dike such as down flow and horseshoe vortex system(HVS)are susceptible to the topographic changes in the local scouring process,resulting in variation of the sediment transport with time.In ...The flow field near a spur dike such as down flow and horseshoe vortex system(HVS)are susceptible to the topographic changes in the local scouring process,resulting in variation of the sediment transport with time.In this study,large eddy simulations with fixed-bed at different scouring stages were conducted to investigate the changes in flow field.The results imply that the bed deformation leads to an increase in flow rate per unit area,which represent the capability of sediment transportation by water,in the scour hole.Moreover,the intensity of turbulent kinetic energy and bimodal motion near the sand bed induced by the HVS were also varied.However,the peak moments between the two sediment transport mechanisms were different.Hence,understanding the complex feedback mechanism between topography and flow field is essential for the local scour problem.展开更多
海上风电桩基的振荡对其局部冲刷的影响不容忽视。该文采用VOF(volume of fluid)两相流模型,对横纵振荡的风电桩基进行数值模拟。分析不同频率、振幅下的桩前和桩侧对称面在周期内流场分布、马蹄涡系变化和床面剪切应力,探究振荡桩基对...海上风电桩基的振荡对其局部冲刷的影响不容忽视。该文采用VOF(volume of fluid)两相流模型,对横纵振荡的风电桩基进行数值模拟。分析不同频率、振幅下的桩前和桩侧对称面在周期内流场分布、马蹄涡系变化和床面剪切应力,探究振荡桩基对局部冲刷的影响机理。研究结果表明:在振荡周期内,纵向振荡桩基桩前对称面内产生回流,在T/2时刻马蹄涡达到最大且床面剪切应力最大,不改变桩侧对称面内水流流动;横向振荡桩基会延展桩侧马蹄涡系,在T/2时刻马蹄涡最大但床面剪切应力最小,T时刻最大,不改变桩前对称面内水流流动。横向、纵向振荡会增大桩前和桩侧的床面剪切应力,加剧局部冲刷,当A=5 mm、f=2 Hz时,纵向振荡桩前对称面剪切应力较静止约增大0.75%,桩侧对称面约增大7%;横向振荡桩前对称面约增大2.5%;桩侧对称面约增大10%。展开更多
基金supported by Shenzhen Science and Technology Program(Grant No.JCYJ20220818102012024)Hong Kong Research Grants Council(Grant Nos.T21–602/16-R and RGC R5037–18)。
文摘The flow field near a spur dike such as down flow and horseshoe vortex system(HVS)are susceptible to the topographic changes in the local scouring process,resulting in variation of the sediment transport with time.In this study,large eddy simulations with fixed-bed at different scouring stages were conducted to investigate the changes in flow field.The results imply that the bed deformation leads to an increase in flow rate per unit area,which represent the capability of sediment transportation by water,in the scour hole.Moreover,the intensity of turbulent kinetic energy and bimodal motion near the sand bed induced by the HVS were also varied.However,the peak moments between the two sediment transport mechanisms were different.Hence,understanding the complex feedback mechanism between topography and flow field is essential for the local scour problem.
文摘海上风电桩基的振荡对其局部冲刷的影响不容忽视。该文采用VOF(volume of fluid)两相流模型,对横纵振荡的风电桩基进行数值模拟。分析不同频率、振幅下的桩前和桩侧对称面在周期内流场分布、马蹄涡系变化和床面剪切应力,探究振荡桩基对局部冲刷的影响机理。研究结果表明:在振荡周期内,纵向振荡桩基桩前对称面内产生回流,在T/2时刻马蹄涡达到最大且床面剪切应力最大,不改变桩侧对称面内水流流动;横向振荡桩基会延展桩侧马蹄涡系,在T/2时刻马蹄涡最大但床面剪切应力最小,T时刻最大,不改变桩前对称面内水流流动。横向、纵向振荡会增大桩前和桩侧的床面剪切应力,加剧局部冲刷,当A=5 mm、f=2 Hz时,纵向振荡桩前对称面剪切应力较静止约增大0.75%,桩侧对称面约增大7%;横向振荡桩前对称面约增大2.5%;桩侧对称面约增大10%。
