Experimental study of the velocity profile at 90° open channel confluence
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摘要: 通过多组次水槽试验,应用声速多普勒测速仪研究入汇角为90°时,不同汇流比水流条件下支流入汇区域及其附近的水面比降变化和时均流速分布特征。试验表明,入汇口上游的干支流水面坡降取决于干支流相互顶托影响,而入汇口处及其下游合流掺混区水面坡降随干流流量增大而增大,随汇流比增大而有所减小。不同位置垂线时均流速分布主要受主支汇流比和水流流态的双重影响,随着汇流比的增大,入汇口上游断面时均流速逐渐减小,而入汇口下游断面产生了明显的高、低流速带,形成回流分离区。Abstract: Based on a large group of the flume experiments and the 3D Acoustic Doppler Velocimeter(ADV),we research the variation of the surface slope and the distribution characteristics of the average velocity around the 90° junction zone with different discharge ratios. And the result shows that the jacking action of the main and the tributary flow has some effect on the surface slope of the upstream of the entrance;the surface slope of entrance and the mixing area of the confluence along the down-stream increases with the rising of the discharge of the main stream,and decreases with the rising of the discharge ratio;the vertical distribution of the averaged velocity of different notes are doubly influenced by the discharge ratio and the flow pattern, to be exact,the average velocity of the upstream of the entrance decreases gradually with the increase of the discharge ratio, while the high and low velocity zone emerges obviously and the separation zone is formed along downstream of the entrance.
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Key words:
- confluence /
- discharge ratio /
- mixing /
- velocity profile /
- distribution character /
- experimental study
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