支流入汇弯曲河段水流运动特性试验研究*

首次对支流与弯曲型干流交汇河段的一般水力学问题进行概化模型试验研究,初步揭示了随着干支流交汇角α和汇流比λ的变化,汇合口河段水面几何形态和纵横比降变化特征、三维流速、水流动力轴线、床面剪切应力等的分布规律,给出了在汇合口下游凹岸一侧出现回流分离区的条件和分离区范围与α和λ的定量关系,并对汇合口河段推移质运动和河床冲淤部位进行了分析,填补了国内外弯道干支流汇合口河段研究的空白,为进一步认识和掌握该类河段水流运动特性奠定了基础。

Experimental research on flow characteristics of inflow of tributaries to curved reach

This paper studies the general hydraulics of the inflow of tributaries to the curved reach by the conceptual model, reveals the variation characteristics of surface geometry and surface slope and distribution law of 3D-velocity,hydrodynamic axis and bed shear stress under various confluence angles and various discharge ratios,presents the condition in which the recirculation zone could appear near the concave bank downstream the junction,and gives the quantitative relationship between the scale of recirculation zone and confluence angle & discharge ratio. This paper also analyzes the bed load movement and riverbed erosion and deposition site at the junction. It lays a good foundation for further study on this kind of rivers.