生态渠道水流阻力形成机理及参数定量化研究

The contradiction between traditional channel and ecological protection has been alleviated as ecological channel proposed. However, it is also realised that the existence of a large number of zeolite, pebbles or vegetation patch in ecological channels strongly affect the flow structure and water supply capacity. Thus, the estimation of flow resistance in ecological channels is a key and theoretical basis for open channel design work. This project based on the experiments and theoretical analysis, systematically studied flow structure over rigid roughness and vegetation patch, and also analysed flow adjustment in ecological channels. A theoretical relationship between the flow resistance and gravity of the primary flow region has been established, the new hydraulic radius calculation model would be obtained from ecological channels. It is also possible to establish the relation between eddy volume and rigid roughness scale or the length and density of vegetation patch. According to analysis the formation mechanism of flow resistance in ecological channel, it is worth to establish the equivalent roughness expression from flow over rigid roughness element or vegetation patch.

渠道的生态改造使得传统渠道输水方式与生态保护的矛盾得到缓解,但生态渠道中大量沸石、卵石或生态带等的存在对于水流结构的变化造成极大影响，也在很大程度上影响了渠道的过水能力。因此，考虑生态渠道中的沸石、卵石或植被对水流的影响并提出水流阻力的定量表达式是实现生态渠道合理设计的理论基础。本项目基于模型试验和理论分析,系统地研究了刚性粗糙元及生态带对生态渠道水流结构的影响，分析水流流经刚性粗糙元或生态带的主要发展过程。基于不同粗糙元作用下水流阻力的力学平衡原理，推导出生态渠道中水力半径计算的调整模型。分析生态渠道水流阻力的形成机理, 重点分析涡旋体积与刚性粗糙元体积或生态带长度及密度的关系，基于涡旋理论建立了同刚性或柔性粗糙元等效阻力的当量粗糙度的表达式。

重点研究生态渠道的水流阻力问题是实现生态渠道合理设计的基础，本项目基于模型试验和理论分析,概化生态渠道中的粗糙元，系统地研究了刚性粗糙元及柔性生态带对生态渠道水流结构的影响，基于不同粗糙元作用下水流阻力的力学平衡原理，推导出生态渠道中水力半径计算的调整模型。分析水流流经刚性粗糙元或生态带的主要发展过程，揭示生态渠道水流阻力的形成机理,建立了同刚性或柔性粗糙元等效阻力的当量粗糙度的表达式。本项目提出的涡旋等效当量粗糙度的计算方法能够应用于生态渠道的设计实践工作中。