漂浮植被作用下水流纵向流速的垂向分布及离散特性研究  

Study on Vertical Distribution of Longitudinal Velocity and Discrete Characteristics in the flow with Floating Vegetation

作　　者：魏煜星 郝瑞霞[1] 任宸剑 韩丽娟[1] WEI Yu-xing;HAO Rui-xia;REN Chen-jian;HAN Li-juan(College of Water Resources Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi Province,China)

机构地区：[1]太原理工大学水利科学与工程学院,山西太原030024

出　　处：《中国农村水利水电》2024年第8期18-24,共7页China Rural Water and Hydropower

基　　金：山西省回国留学人员科研资助项目(2021-051);长江科学院开放基金项目(CKWV2021869/KY);山西省基础研究项目(202103021223079);山西省水利科学技术研究与推广项目(2022GM017)。

摘　　要：为探究漂浮植被影响下明渠水流流速及纵向离散系数的沿程变化特性,采用Fluent软件中的k-ε模型进行三维数值模拟并与水槽试验结果进行对比分析,在模型验证合理的基础上,对漂浮植被不同根系下探深度及覆盖率下水流纵向时均流速的垂向分布特性进行研究,并基于改进的分区模型分析了含漂浮植被明渠的纵向离散系数。结果表明:漂浮植被水流垂向上可分为含植被水流层、无植被水流层与近河床层。纵向流速最大值出现在无植被水流层,其大小与植被下探深度及覆盖率呈正相关。含植被水流层的纵向流速随植被根系下探深度和覆盖率的增加而减小,无植被水流层及近河床层的纵向流速随着下探深度和覆盖率的增大而增大,且植被覆盖率及下探深度越大含植被水流层与无植被水流层的流速差异越大。纵向离散系数沿程表现出先增大后减小的趋势,在植被区中下游离散最为剧烈,且与植被下探深度和覆盖率呈正相关。To investigate the along-range variation characteristics of flow velocity and longitudinal dispersion coefficients of water flow in open channels under the influence of floating vegetation,in this paper,a three-dimensional numerical simulation was carried out by the k-εmodel in Fluent software,and compared with the results of flume tests.On the basis of reasonable model validation,the vertical distribution characteristics of longitudinal time-averaged flow velocity of water with different depths of root into water and coverage rates of floating vegetation were investigated.The enhanced N-zone model served as the basis for the analysis of the longitudinal dispersion coefficient.The results showed that the vertical structure of floating vegetated flow could be divided into vegetated flow layer,non-vegetated flow layer and near-riverbed layer.The depth of the vegetation root into the water and the covering rate were connected to the maximum longitudinal velocity,which was found in the non-vegetated flow layer.While the longitudinal velocity in the near-riverbed layer and non-vegetated flow layer increased with increasing coverage rate and depth of vegetation root into water,the longitudinal velocity in the vegetated flow layer decreased with increasing coverage rate and depth of vegetation root into water.The greater the vegetation coverage rate and the depth of root into water,the greater the velocity difference between the vegetated flow layer and the non-vegetated flow layer.The longitudinal dispersion coefficient showed a tendency of first increasing and then decreasing along the streamflow direction,with the sharpest dispersion in the middle and lower reaches of the vegetation zone,and was positively correlated with the depth of vegetation root into water and coverage rate.

关 键 词：漂浮植被 纵向时均流速 纵向离散系数 根系下探深度 植被覆盖率 

分 类 号：TV133.1[水利工程—水力学及河流动力学]