蜿蜒河流动力过程非线性特征及其长期响应机制

Meandering river, as the most common river morphology in nature, changes its surface morphology with time under the impetus of its own inherent power, such as wriggling, migration and detour. The periodic and quasi-periodic meandering dynamic process as well as the response to the disturbance are the concentrated expression of the characteristics of river nonlinear dynamic process. For instance, the river filtering function and the river butterfly effect are the river stabilization and scattered trend, respectively. Therefore, associated with the large scale meandering river, this project investigates the nonlinear characteristics of river morphology and the river dynamic process. In addition, it establishes the nonlinear theory of meander river evolution, including the differential geometric statistical models of river morphology, the nonlinear mechanics equations of river evolution, explanation of chaotic mechanics of large-scale river morphology, theoretical analysis of the river evolution process at the middle and lower reaches of Yellow River and Yangtze River, etc. The investigation of the nonlinear characteristics of river dynamic process and the long-term response mechanism is significant to the understanding the river dynamic process and the development of river mechanics. Moreover, it also essential to study the water discharge, sediment transport behaviour in floodplain and effects to bank collapse after the construction of huge dam, such as Three Gorges.

蜿蜒河流作为自然界中最常见最典型的河流形态，在其自身内在动力的推动下，随着时间变化不断摆动、迁移和迂回，其周期和准周期的蜿蜒动力过程以及受扰动后的响应机制，如："河流滤波功能"，即河流稳定化趋向；"河流蝴蝶效应"，即河流散乱化趋向等,这些都是河流动力过程非线性特征的集中体现。因此，项目以蜿蜒河流为背景，对大型蜿蜒河流平面形态的非线性特征、动力过程的非线特征等进行研究，建立蜿蜒河流动力演变过程的非线性理论模式，包括：蜿蜒河流形态的微分几何统计模式、蜿蜒河流动力演变的非线性力学方程、大型河流形态学的混沌力学解释、长江典型蜿蜒河段动力演变过程理论分析等研究内容。.蜿蜒河流动力过程非线性特征及其长期响应机制问题研究，对正确理解河流动力过程、推动河流力学发展，具有重要的学科意义；对正确认识三峡等大型水库建成后，清水下泄与流域来沙条件改变对河势及崩岸影响，具有重要的现实意义。

本课题的研究目标是在建立河流细观动力过程理论模式的基础上，进行“ 蜿蜒河流动力过程非线性特征及其长期响应机制” 的研究，达到正确理解蜿蜒河流动力过程、推动河流动力学发展、完善非线性河流动力学理论。探讨弯曲型河流河床形态多样性、滩槽生成与泥沙交换、弯曲型河流河弯演化的力学机理，建立相应的理论模式和预测数学模型，为今后黄河、长江下游河段的进一步整治提供指导和依据，为以后河流整治工程的优化设计提供科学依据。