非淹没刚性挺水植被对弯道水流特性的影响  

Influence of non-submerged rigid vegetation on the flow characteristics of bend

作　　者：赵瑜琪 彭清娥[1] 史学伟 杨克君[1] ZHAO Yuqi;PENG Qing’e;SHI Xuewei;YANG Kejun(State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,四川成都610065

出　　处：《水利水运工程学报》2021年第6期80-88,共9页Hydro-Science and Engineering

基　　金：国家重点研发计划资助项目(2018YFC0407302);国家自然科学基金资助项目(51539007)。

摘　　要：广泛分布于天然河道浅滩的植被能够改变河流局部的水力特性和泥沙运移过程,为了解植被对弯道水流特性的影响,针对特定流量下凸岸侧含有刚性挺水植被的弯道,对植被密度、位置不同时水流特性的沿程分布规律开展试验探究。通过建立弯道水流概化模型,利用ADV采集三维流速数据,对比无植被和有植被(植被密度分别为0、2.2%和4.5%)条件下的流速分布,定性分析不同工况下植被对弯道水流紊动特性的作用,确定弯道环流的结构及强度。结果表明,凸岸侧植被的存在(在0°~90°弯段,1/4河宽区间内均匀分布)能有效削弱弯道环流强度,但对凸岸区的消减效果并不随植被密度的增大而加强。非植被区上下不同流向水层的分界点位置随植被密度变化而变化,且植被分布对弯道各断面不同水深处的环流结构也有影响。Vegetation widely distributed in natural river shallows can change the local hydraulic characteristics of the river and the process of sediment transport.In order to understand the influence of vegetation on the flow characteristics of the bend,our experiment is aimed at the bend with rigid emergent vegetation on the convex bank under a specific flow rate,to explore the distribution law of water flow characteristics along the way when vegetation density and location are different.By establishing a generalized model of curved water flow,using ADV to collect and process the three-dimensional velocity data,and comparing the velocity distribution under the conditions with and without vegetation(vegetation density respectivelyρ=0,ρ=2.2%,ρ=4.5%),we qualitatively analyze the effect of vegetation on the turbulence characteristics of the curve flow under different working conditions,and determine the structure and strength of the curve circulation.The results show that the existence of vegetation on the convex bank(0°-90°bend,evenly distributed in the quarter of the river width)can effectively weaken the circulation intensity of the bend,but the reduction effect on the convex bank area does not increase with the increase of vegetation density.The location of the dividing point of different flow direction water layers in the non-vegetation area changes with the change of vegetation density,and the distribution of vegetation also affects the circulation structure at different water depths in each section of the bend.

关 键 词：刚性植被 弯曲河道 速度分布 横向环流 紊动特性 

分 类 号：TV143[水利工程—水力学及河流动力学]