交汇角和流量比对干支流交汇区水流结构影响模拟研究  

Study on the Influence of Intersection Angles and Confluence Ratios on the Flow Structure in the Intersection Area of Main and Branch Rivers

作　　者：吴菲 刘瑞芬 白凤朋 尹炜 WU Fei;LIU Rui-fen;BAI Feng-peng;YIN Wei(College of Civil Engineering and Environment,Hubei University of Technology,Wuhan 430068,Hubei Province,China;Changjiang Water Resources Protection Institute,Wuhan 430051,Hubei Province,China;Key Laboratory of Ecological Regulation of Non-point Source Pollution in Lake and Reservoir Water Sources,Changjiang Water Resources Commission,Wuhan 430051,Hubei Province,China;Intelligent Yangtze River Innovation Team,Wuhan 430051,Hubei Province,China)

机构地区：[1]湖北工业大学土木建筑与环境学院,湖北武汉430068 [2]长江水资源保护科学研究,湖北武汉430051 [3]长江水利委员会湖库水源地面源污染生态调控重点实验室,湖北武汉430051 [4]长江水利委员会智慧长江创新团队,湖北武汉430051

出　　处：《中国农村水利水电》2024年第4期15-23,共9页China Rural Water and Hydropower

基　　金：国家自然科学基金项目(U2040210);国家自然科学基金青年科学基金项目(51909081)。

摘　　要：弱混合条件下下干流对支流入汇区水流结构影响显著,支流入汇区水流特性复杂,弄清支流入汇区水动力特性对河流的生态修复、水环境治理等问题具有重要意义。研究采用物理模型和数值模拟结合的方法,构建并验证明渠干支流交汇RNG k-ε紊流模型,根据不同交汇角弱混合多种汇流比工况计算结果,详细分析了交汇角和汇流比的变化对支流入汇区流速分布特性和环流结构的影响,并计算分析得出不同交汇角支流入汇区发生回流汇流比的临界值。结果表明:干支流交汇弱混合条件下,干流对支流入汇区水流结构影响显著。支流水流在入汇区在右岸出现回流形成回流区,并右岸壁面处形成最大回流流速区;支流入汇区表中层形成大尺度的横向涡结构,出现了明显回流区和环流结构,环流结构尺度随着汇流比的增大而减小,与交汇角的相关关系表现为150°大于30°大于90°;纵向涡量峰值与汇流比均呈负相关关系,汇流比越大,涡量峰值越小;交汇角30°、90°和150°支流入汇区发生回流,出现环流结构的汇流比γ临界值分别为0.013、0.011、0.031。Under the weak mixing condition,the main inflow has a significant effect on the flow structure of the branch inflow convergent ar⁃ea,and the flow characteristics of the branch inflow convergent area are complex.It is of great significance to understand the hydrodynamic characteristics of the branch inflow convergent area for ecological restoration and water environment management.In this study,the RNG k-εturbulent flow model for the intersection of trunk and tributaries of open channel was constructed and verified by the combination of physi⁃cal model and numerical simulation.Based on the calculation results of weakly mixed multiple confluence ratios at different intersection an⁃gles,the influence of changes in intersection angles and confluence ratios on the velocity distribution characteristics and circulation structure in the branch convergent area was analyzed in detail.The critical value of the ratio of return flow in the different junction angles is calculated and analyzed.The results show that the main flow has a significant influence on the flow structure of the branch inflow area under the condi⁃tion of weak mixing.In the convergent area,the flow of the tributary flows back to form a return zone on the right bank,and the maximum re⁃turn velocity zone is formed on the right bank wall.A large-scale transverse vortex structure is formed in the middle surface of the branch in⁃flow convergent area,and there are obvious backflow area and circulation structure.The circulation structure scale decreases with the in⁃crease of the convergence ratio,and the correlation between the intersection angle is 150°>30°>90°.The longitudinal vorticity peak value is negatively correlated with the confluence ratio.The larger the confluence ratio is,the smaller the vorticity peak value is.Backflow occurs in the tributaries at intersection angles of 30°,90°and 150°.The critical values of the confluence ratioγof the circulation structure are 0.013,0.011 and 0.031,respectively.

关 键 词：干支流交汇 弱混合 数值计算 水动力特性 

分 类 号：TV143[水利工程—水力学及河流动力学]