多分汊河型水流结构概化模型试验研究

Experimental study on generalized model of braided river flow structure

针对多分汊河段,以长江下游典型多分汊河段东流水道为基础,制作河道概化模型开展系列试验,探究不同来流条件下河道复杂的水流结构特点。试验结果显示来流条件及河床边界条件均会影响多分汊河道的流速分布;水流动力轴线的分布在多分汊河道中同样呈现"大水趋直,小水走弯"的特点;各分汊段输沙能力对比呈现不同的结果;河道中各处紊动强度由水面向河底增大,并在局部出现高紊动能区域。

Dongliu Waterway is a typical braided channel in the lower reaches of the Yangtze River. The river generalization model of Dongliu Waterway was produced and a series of experiments were carried out so as to explore the complex water flow structure characteristics of the river channel under different inflow conditions.The experimental results show that both the inflow conditions and the riverbed boundary conditions affect the flow velocity distribution of the braided channels;the water flow dynamic axis also has the characteristics of"Great water goes in a straight line, while little water goes in a curve"in the braided channel;the sediment transport capacities vary in different channel reaches;the turbulence intensity in the river channels increases from the water surface to the river bottom, and high turbulent kinetic energy regions appear locally.