弯曲型交汇河口三维数值模拟研究

Three-Dimensional Numerical Simulation of Flows in Bend River Junction

弯曲型主渠交汇是天然河流的主要交汇形式,对河床演变和水运发展产生重要影响,为了研究弯曲型交汇河口的水力特性,首先通过实验值与模拟值进行对比进行模型验证,然后通过三维数值模拟研究了流量比为0.250、0.417、0.750时,支渠分别交汇于120°弯曲主渠弯顶凹岸和凸岸的交汇口附近的水流特性,从而为进一步研究弯曲型交汇河口的动床水流创造条件。通过研究表明:相同流量比的情况下,凸岸交汇时,分离区大,凹岸交汇时,分离区小;流量比越小,上游雍水越高,交汇口下游最低水位越低;相同流量比,凸岸交汇时上游雍水大于凹岸交汇,下游最低水位低于凹岸交汇,上下游水位差更大。

The intersection of curved main channels is the main form of natural rivers,which plays an important role in riverbed evolution and water transport development.To analyze the hydraulic characteristics of the bend river junction,we firstly verified the three-dimensional model by comparing the experimental values with the simulated values,and good agreement was obtained between the model simulation and the experimental measurements.Then the flow characteristics under the flow ratios 0.25、0.417、0.75 was analyzed when the tributaries meet at the 120-degree angle to the main stream from Concave bank and convex bank which will create environment for further study of moving bed flows in bend river junction.The results show that:under the same flow ratio the separation zone when the tributaries meet main stream at convex bank is larger than the concave bank;the smaller the flow ratio,the higher the upstream water level and lower the downstream water level.Under the same flow,the upstream water level when junction at concave bank is higher than junction at convex bank.