基于数值模拟方法的大曲率弯道演变机理研究

项目名称： 基于数值模拟方法的大曲率弯道演变机理研究

项目编号： No.51509234

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 水利工程

项目作者： 张世彦

作者单位： 中国科学院地理科学与资源研究所

项目金额： 20万元

中文摘要： 本项目拟借助数值模拟方法对大曲率弯道的演变机理开展研究。首先通过耦合水沙运动和河道迁移的基本控制方程，在现有模型基础上建立不受曲率限制的弯道演变数值模型，模拟弯道演变中的流场结构与河道迁移过程；然后利用数学模型可以分离物理过程的优势，逐一测试水面和床面坡度、曲率变化、主流动量再分布、横向流动等变量在弯道发展的不同阶段对弯道演变的贡献度和敏感度；最后分析线性模型和非线性模型的模拟结果差异及其成因，并探讨大曲率弯道演变的主要控制参数及其影响机理。本项目的实施能够为弯道演变数值模拟提供理论上更为完善的模型工具，其研究成果能够深化人们对大曲率弯道演变机理的认识，并为我国弯曲型河道的整治和管理实践提供理论支持，因此具有重要的科学和工程意义。

中文关键词： 次生流；弯曲半径；非线性理论；蜿蜒；横比降

英文摘要： This project proposes to investigate the evolution dynamics of sharp meander bends with numerical simulation method. A meander evolution numerical model based on existing models with no curvature restrictions will be established by coupling the basic governing equations for water-sediment movement and channel migration, and flow structure and channel migration in meander evolution will be simulated. By taking advantage of the mathematical model in which physical processes can be separated, the contribution and sensitivity of each individual term including transverse water surface and bed slope, curvature change, streamwise momentum redistribution and cross flow on meander evolution processes at different stages of evolution will be sequentially tested. The differences between the simulated results of the linear and nonlinear models and their causes will be analyzed, and the dominant parameters for the evolution processes of sharp meander bends and their influencing mechanisms will also be discussed. The implementation of this project will not only provide a theoretically improved modeling tool for the numerical simulation of meander evolution processes, but also deepen our understanding of the evolution dynamics of sharp meander bends and lend theoretical support to the regulation and management activities of meandering rivers in China, and is therefore of great significance in scientific and engineering practices.

英文关键词： Secondary flow;Radius of curvature;Nonlinear theory;Meandering;Transverse slope