Downward seepage effects on flow near a L-shape spur dike and bed morphology  

作　　者：Harish Kumar Patel Meilan Qi Bimlesh Kumar 

机构地区：[1]Department of Civil Engineering,Indian Institute of Technology Guwahat,Guwahati 781039,India [2]School of Civil Engineering,Beijing jiaotong Universit,Beijing 100044,China

出　　处：《International Journal of Sediment Research》2024年第2期194-208,共15页国际泥沙研究（英文版）

摘　　要：Spur dikes are structures built along riverbanks that serve two purposes:stabilizing the banks and minimizing erosion risk by controlling water flow in the river channel.The current study used L-shaped spur dikes in an alluvial channel to analyze the bed morphology and flow pattern in the spur dikes zone with the influence of no-seepage and two distinct seepage velocities,Vsi=0.075 mm/s and Vs2=0.15 mm/s near the channel bed z/h<0.2.The experimental study was also done to examine and compare the transformation in the local scour depth for the seepage condition.According to the study results,downward seepage movement causes significant modification in the channel's bed elevation and the development of scour depth.Observations indicate that the maximum local scour occurs at the first spur dike's leading edge.Seepage velocity Vsi results in a 16.1%increase in the maximum scour depth compared to the no-seepage scenario.In comparison,seepage velocity Vs2 causes an increase of 25.2%in the maximum scour depth.Due to downward seepage,the flow distribution is shifted down near the channel's boundary.With an increase in the seepage rate,the magnitude of velocity,Reynold shear stress,turbulent kinetic energy,and bed shear stress also rise close to the channel's boundary.The current study also examined bursting events near the channel's bed under seepage and no-seepage conditions.These events included outward interaction,inward interaction,ejection,and sweep.Quadrant analysis of velocimeter data revealed that ejection and sweep were the dominant events contributing to the production of Reynolds shear stress in seepage and no-seepage flows.Meanwhile,outward interactions and inward interactions made minor contributions compared to ejection and sweep events to theReynolds shear stress.

关 键 词：Downward seepage Spur dikes Bed morphology Local scour depth Flow pattern Bursting events 

分 类 号：TV863[水利工程—水利水电工程]