摘要
床面剪应力诱发了水流垂向上流速分布不稳定性,压力和向心力不均则促使水流形成了弯道二次流.通过试验,研究了近临界弯曲比率(R/B=3)条件下,小宽深比(B/H=2)水槽中水流变化及泥沙输移特性.研究结果表明:二次流强度最大值出现在弯顶区域,床面剪应力最大值出现在弯顶偏凸岸一侧.弯道床面附近,不同层面上的剪应力最大值,从上游到下游先增大后减小;不同平面动力轴线随层面的高度增加而向凹岸偏离.二次流在不同断面形成不同的涡核,在弯道入口附近产生分离而在弯道下游逐步发展,涡核合并,二次流强度在弯顶区达到最大值.最后对二次流和床面剪应力作用下的床面形态结果进行分析.
Bed shear stress mightily induces the instability of velocity distribution in vertical direction,and nonuniformstress and centripetal force of water flow cause secondary flow in channel bends.In this study,the changesof water flow and sediment transport characteristics in flume under a small wide depth ratio(B/H=2)and the nearcriticalcurvature ratio(R/B=3)were investigated.The results show that the maximum secondary flow strength is locatedat the apex of bend,and bed shear stress reaches its maximum at the apex of upstream,which is closer to theconvex bank.On the other hand,near the bed,the maximum of shear stress at different levels firstly increases andthen decreases from the first half of channel bend to the second half.At different levels,the flow dynamic axis skewsto concave with the increase of level height.As for the secondary flow in channel bends,various vortex cores form indifferent sections,which will firstly be separated near the entrance of channel bend,then gradually evolve towardthe downstream,and merge together in the end.Ultimately,the analyses of the bed results were presented,considering the interactions between secondary flow and bed shear stress.
作者
高术仙
徐海珏
白玉川
Gao Shuxian;Xu Haijue;Bai Yuchuan(State Key Laboratory of Hydraulic Engineering Simulation and Safety (Tianjin University),Tianjin 300072,China;Institute for Sedimentation on River and Coastal Engineering,Tianjin University,Tianjin 300072,China)
出处
《天津大学学报（自然科学与工程技术版）》
EI
CSCD
北大核心
2017年第7期717-724,共8页
Journal of Tianjin University：Science and Technology
基金
国家自然科学基金资助项目(51279124
51021004
50979066)~~
