明渠交汇口水流分离区研究

支流汇入主流后,在明渠交汇口下游附近形成分离区,造成过流断面束窄.采用水力学基本理论及试验手段,对等宽明渠交汇口水流分离区的形状及尺寸进行了理论分析和试验研究,提出了分离区收缩系数及能量损失系数的理论表达式并与试验结果进行了比较.研究结果表明,随交汇角或主支流流量相对大小不同,分离区尺寸发生变化;对于给定交汇口几何形状及尺寸,分离区形状基本保持不变,但分离区尺寸随流量比变化并具有较好的相关关系,并随交汇角增大呈有规律增加.

Study on the separation zone in open-channel junction

The separation zone develops immediately downstream of the open-channel junction when branch flow enters, resulting in contraction of channel cross-section. This particular hydraulic characteristic influences significantly the local sedimentary processes, channel scour and sidewall erosion. Based upon the experimental investigation and theoretical analysis, the shape and size of the separation zone are studied, and the formulations for both contraction coefficient and energy loss coefficients are presented, together with the comparisons with experiment results. Both the analytical solutions and the experiment results indicate that for the given junction angle the shape of the zone remains essentially constant. The fine relationships show the both width and the length of the separation zone increase either as discharge ratio or junction angle increases.