基于弗劳德数Fr与相对水流强度η*关系的弯曲河道演变过程及规律研究

Meandering river is one of the most common and most basic patterns in natural alluvial rivers. To understand the fluvial processes of meandering rivers is very important to both academic research and engineering practices on river sedimentation and processes, however, so far the meandering river processes is still not fully explored clear yet, and remains currently one of the unresolved difficult problems and the hot study issues in river engineering. On the basis of previous research in this area and after exploring fully in this study, it is considered that the relationship between river flow Froude number Fr and relative flow intensity η* can further reveal the fluvial processes of natural meandering rivers. So that in this study, the abovementioned relationship becomes the basic research guide, the theoretical analysis, physical modeling and numerical simulation then become the comprehensive research methods to establish a series of three-dimensional mathematical model experiments of water flow and sedimentation on meandering rivers, supplemented by physical model tests for the river fluvial processes. The reasonable relationship results between river flow Froude number Fr and relative flow intensity η* will eventually reveal the basic law of fluvial processes of natural meandering rivers. This study also strives to make a contribution to the fundamental theories on fluvial process of natural meandering rivers and provides new ideas and experiences for future research in this area.

弯曲河道是天然冲积河流中最常见和最基本的河型之一。弄清弯曲河道的演变规律无论是对河流泥沙及演变的学术研究还是对河流的工程实践都具有非常重要的意义，然而，迄今为止弯曲河道的演变规律尚未能被完全探索清楚，仍然是当前河流泥沙及演变研究的热点问题和尚未解决的难点问题之一。本研究在前人研究成果的基础上，经充分论证后认为，探索弗劳德数Fr与相对水流强度η*之间的关系可以进一步揭示天然冲积河流的演变规律，为此，将该关系作为本研究的基本指导，运用理论分析、物理试验和数值模拟三种研究手段建立以三维水沙数学模型实验为主、弯曲水槽物理模型试验为辅的综合实验研究方案，针对弯曲河道自然演变的过程展开模拟和分析，描绘其演变过程中弗劳德数Fr随相对水流强度η*变化的关系曲线，借此揭示弯曲河道自然演变的基本规律，力求在弯曲河道自然演变的理论方面有所建树，并为今后该方面的研究提供新的思路和借鉴。

探索弯曲河道的演变规律是当前河流泥沙及演变研究的热点及难点问题之一，对河流泥沙及演变的学术研究以及对工程实践都具有非常重要的意义。本研究采用了数学模型实验为主、物理模型试验为辅的“综合实验方案”进行研究，经充分论证后认为，探索弗劳德数Fr与相对水流强度η*之间的关系可以进一步揭示天然冲积河流的演变规律。在此基础上针对长江中下游的典型弯段进行建模，通过收集长系列水文、泥沙资料作为计算条件、长系列地形资料作为验证条件，复演并预测这些典型弯段的演变过程，描绘其演变过程中弗劳德数Fr随相对水流强度η*变化的关系曲线，揭示了弯曲河道自然演变的基本规律，可以为实际工程问题研究提供理论支持。