植被作用下的交汇河道水流结构及泥沙输移规律的试验研究

In the process of the prevention and control of flood-sediment disaster,besides the engineering measurment of confluent stream training, vegeation is also very important. Due to the influences of vegetation and the shape of the channel, the flow structure,seidment transport and fluvial processes in the confluent streams with vegetation is considerably more complex than that in the confluent streams without vegetation. Through flume experiments, the applicants will investigate three deimensional turbulent flow structure, formation mechanism of secondary flows, momentum transfer and energy loss mechanism, flow resistance, stage-discharge relationship, incipient motion condition and transport of sediment, explore the the effects of secondary flow and vegetation on channel change, and propose the physical picture of flow movement and sediment transport in the confluent streams with vegetation. On the basis of the understanding of the flow structure and sediment transport mechanism, applying the related theories of fluid mechanics and river dynamics, the applicant will invegstigate the computational metheds for velocity distribution,develop the computational method of flow resistance, and the computational methods of conveyance capacity and bedload movement in the confluent streams with vegetation, which will perfect and update the theory and method related to the flow strutcure and bedload motion in the confluent streams with vegetation. The research results of the project will enrich the research contents of hydraulic and river dynamics and will provide the theoretical and technical supports for river ecological restoration, flood control and disaster reduction, construction of urban ecological hydraulic engineering, etc.

在洪水泥沙灾害防治和河流生态修复的过程中，交汇河道治理途径除工程措施外，植被等生物措施亦十分重要。植被作用下的交汇河道由于水流、植被和泥沙耦合作用，水沙运动规律复杂，其研究为河道水动力学的前沿基础课题之一。本申请课题拟通过系统的水槽试验，研究植被作用下的交汇河道紊流结构、二次流运动模式、动量交换及能量损失特性、水流阻力特性、水位流量关系、泥沙输移规律，并建立该类河道水沙运动的物理图形。在探明水流结构及泥沙输移规律的基础上，以流体力学、河流动力学理论为基础，探讨植被作用下的交汇河道流速分布、水流阻力的计算方法，并构建该类河道流量预测和推移质运动的计算方法，实现交汇河道水流结构研究在理论与方法上的完善和更新。研究成果将丰富和完善水力学及河流动力学的研究内容，为防洪减灾、河流生态修复、水环境保护、河道治理等提供理论依据和技术支撑。

在洪水泥沙灾害防治和河流生态修复的过程中，交汇河道治理途径除工程措施外，植被等生物措施亦十分重要。植被作用下的交汇河道由于水流、植被和泥沙耦合作用，水沙运动规律复杂，其研究为河道水动力学的前沿基础课题之一。本申请课题通过系统的水槽试验，研究了植被作用下的交汇河道紊流结构、动量交换及能量损失特性、水流阻力特性、水位流量关系、泥沙起动及输移规律，探讨了植被对河道演化的影响，并建立该类河道水沙运动的物理图形。通过水槽试验与理论分析，探明了该类河道流速分布、紊动水流结构、雷诺应力空间布特性等，揭示了植被对推移质输移以及河床演变特性的影响机理，实现了交汇河道水流结构及泥沙输移研究在机理与方法上的完善和更新。研究成果将丰富和完善水力学及河流动力学的研究内容，为防洪减灾、河流生态修复、水环境保护、河道治理等提供理论依据和技术支撑。