主支汇流比对交汇区域水流脉动特性影响试验

通过多组次水槽试验,应用ADV研究入汇角为90°时不同汇流比水流条件下交汇区域的三维水流结构及其脉动特性。试验表明:支流汇入后,将对主流上游水面产生顶托影响,使得主支流水位不仅是各自流量的函数,还与主支流流量比大小有关。入汇口上游断面受影响范围很小,但下游断面受影响范围较大,越靠近入汇口一侧,受影响程度越大,影响范围接近入汇口下游收缩区外侧的剪切面。入汇口下游的主流边壁(靠近入汇口一侧)的分离区附近水流脉动强度和雷诺应力均较大,回流现象很明显,水面呈现极不规则的扭曲面。入汇口下游主流右侧(靠近分离区附近)在相对水深z*=0.2附近处,x和y方向的脉动强度易出现极大值。

Experiment on the influence of discharge ratio of main flow of tributary on flow fluctuation characteristics in confluence area

Based on multiple flume experiments,the three-dimensional flow structure and its fluctuation characteristics in the confluence area,with different discharge ratios of the main channel to the tributary at junction angle 90°,are studied with ADV.The tests indicate that,beyond the confluence,the surface of the main channel upstream is influenced by the jacking action and the water level of the main flow,and tributary flow is correlated not only with each flow's discharge but also with the discharge ratio.The influence range is quite small upstream of the entrance,and greater downstream.The influence is stronger nearer the entrance.The influence range approaches the shear plane near the side of entrance.In the distribution range downstream from the entrance(near the side of entrance),both the turbulence intensity and Reynolds stress are greater,and the back flow is obvious,showing a very irregular warp surface.On the right-hand side of the main flow downstream from entrance(near the distribution range),the turbulence intensity of x and y tend to reach their maximum values,while the relative water depth z*=0.2.