含漫滩植被生态河道中水流流速沿程发展的解析解  

Analytical Solution of Flow Velocity Development Along Ecological Channel Containing Floodplain Vegetation

作　　者：张皎 苗萌萌 王雯[1] 米章毅 陈文夫 伍梓 Zhang Jiao;Miao Mengmeng;Wang Wen*;Mi Zhangyi;Chen Wenfu;Wu Zi(State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi’an University of Technology,Xi’an 710048,China;Anhui Water Resources Development Co.,Ltd.Hefei 230000,China;State Key Laboratory of Hydroscience and Engineering,Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]西安理工大学省部共建西北旱区生态水利国家重点实验室,西安710048 [2]安徽水利开发有限公司,合肥230000 [3]清华大学水沙科学水利水电工程国家重点实验室,北京100084

出　　处：《水动力学研究与进展（A辑）》2023年第2期319-327,共9页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金(52109100;U2040208);清华大学水沙科学水利水电工程国家重点实验室及宁夏银川水联网数字治水联合研究院联合开放研究基金资助课题(sklhse-2023-Iow06);中国博士后科学基金面上资助(2021M702643);安徽水利开发股份有限公司资助(KY-2021-13)。

摘　　要：在生态河道中,非淹没水生植被通常顺着水流方向生长在河岸附近,形成一个宽度有限的长条形植被区,所致的水流空间异质性远高于以往研究所关注的植被完全覆盖河道的情况。水生植被生态功能的正常发挥与否,受植被区内水流流速的影响,因此有必要对植被作用下的河道水流纵向发展情况进行研究。该文基于指数衰减模型理论,对任一横断面上的植被区和非植被区内纵向流速的横向分布进行分析预测,对模型中的参数(水流调整长度XD和植被拖曳力系数Cd)逐一讨论并给出了详细表达式,研究发现不同学者提出的XD求解公式对于横向流速场的求解影响较小,而Cd对于水流流速调整过程中横向剖面上的纵向流速分布情况有较大影响。将含有柔性和刚性漫滩植被水流的实测或模拟流速数据与该研究的流速预测值进行对比验证,发现预测值在不同纵向位置处的速度分布与以往实验和模拟流速数据吻合较好,表明该模型对含有漫滩植被复杂速度场具有可观的适用性。In ecological river channels,non-submerged aquatic vegetation usually grows near the riverbank along the direction of water flow,forming a strip vegetation area with limited width.The spatial heterogeneity of water flow caused by this area is much higher than the situation of complete vegetation coverage in previous studies.The ecological function of aquatic vegetation is affected by the flow velocity in the vegetation area.Therefore,it is necessary to study the development of the flow velocity along the river under the action of vegetation.In this paper,based on the theory of exponential attenuation model,the transverse distribution of longitudinal velocity is analyzed and predicted at any cross section.The parameters in the model,namely,water flow adjustment length XD and vegetation drag force coefficient Cd,are discussed and given in detail.It is found that the solution formula of XD proposed by previous scholars has little influence on the transverse profile of velocity field,while Cd has great influence on the longitudinal flow velocity distribution in the process of flow velocity adjustment length.The predicted velocities are compared with the velocities obtained from previous experiments and numerical simulation on the flexible and rigid vegetation.It is found that the velocity distribution of the predicted values at different longitudinal positions is in good agreement with the previous experimental or simulated flow velocity data,indicating that the model has promising applicability to the complex velocity field with floodplain vegetation.

关 键 词：漫滩植被 水流纵向发展 纵向流速 横向分布 

分 类 号：TV133[水利工程—水力学及河流动力学]