多层植被作用的水流运动及物质输移规律研究

Vegetation is an important part of landscape river, ecological river, and artificial wetland construction. Multilayer vegetation flow have the characteristics of the open channel flow, porous media flow and boundary layer flow. The law of flow motion and substance transport is very complex. The method of theoretical analysis, numerical simulation and flume experiment will be adopted to investigate the law of flow motion and substance transport under the action of multilayer vegetation. Firstly, the Biot's theory of flow in porous media is used to obtain the velocity and shear stress distribution formula in each layer, and to provide theoretical guidance for the numerical simulation and experimental study; Secondly, the flume experiment is used to simulate flow movement and pollutant transport in multilayer vegetation flow, the measurement data of velocity and concentration field is used to reveal the interaction mechanism between vegetation, water and pollutant; At the same time, by algebraic stress model and large eddy simulation theory, a turbulent model and water quality model will be build to predict and simulate flow motion and pollutant movement under the action of multilayer vegetation. Finally, based on the results of theoretical analysis，flume experiment and numerical simulation, the quantitative law of flow motion and pollutant transport in vegetation layers will be determined to provid a scientific basis for the design of ecological landscape river, the construction of artificial wetland, the evaluation of river flood control and the assessment of water environment.

植被是景观河道、生态河道、人工湿地建设中的重要组成部分。多层植被同时作用于水体时，水流兼有明渠流、孔隙介质流及边界层流动等的特性，其运动规律和物质输移规律十分复杂。本项目拟采用理论分析、数值模拟和水槽实验相结合的方法，研究多层植被作用下的水流运动及物质输移规律。首先采用Biot的孔隙介质流动理论，推导多种植被同时作用下各层水流的流速和切应力分布公式，为数值模拟和实验研究提供理论指导；其次利用水槽实验模拟多层植被中的水流及污染物运动，通过对流场及浓度场的测量和分析，揭示植被、水体和污染物之间的相互作用机理；同时，应用代数应力模型和大涡模拟理论，建立相应的紊流模型和水质模型，模拟预报多层植被作用下的水流及污染物运动；最后，结合理论分析、水槽实验和数值模拟结果，定量确定各植被层中的水流运动和污染物输移规律，为生态景观河道设计、人工湿地建设、防洪评价及水环境评价等提供科学的参考依据。

植被是生态景观河道、人工湿地建设中的重要组成部分，研究植被水流运动及物质输移规律具有理论意义和实际意义。项目采用理论分析、实验研究、数模模拟相结合的方法，研究了多层植被作用下的河道水流结构及污染物输移规律。主要研究内容为：(1)明渠均匀流的水力最佳断面设计、水流结构及流速分布规律研究；(2)采用Biot理论和力的平衡方程建立了植被水流的控制方程，求出了相应的分析解；(3)采用水槽实验研究多层植被作用下的水流运动规律及污染物扩散规律；(4)建立三维水动力学紊流模型以及污染物扩散输移模型，结合理论分析、水槽实验和数值模拟结果，定量确定各植被层中的水流运动参数和污染物扩散参数。研究成果可以为生态景观河道设计、人工湿地建设、防洪评价及水环境评价等提供科学的参考依据。