断面形态对弯道交汇水流环流结构影响的数值模拟

Numerical simulation on effect of the cross-section on flow structures in confluent main bend channel

在模型试验的基础上,采用RNGκ-ε湍流模型和刚盖假定处理自由水面的数学模型,对有支流入汇的弯道水流进行数值模拟。分析在交汇角可变的情况下,不同的河道断面形态对弯曲交汇河段横断面环流结构的影响,发现在相同圆心角断面处,复式河道断面的环流个数较多。在两种断面形态中,交汇角的变化,对上游断面及交汇断面处的环流结构影响都较明显。但交汇区域下游,交汇角的变化,对偏V型横断面的环流数量的影响较大,对复式河道横断面的环流结构的数量影响较小。由此可知,断面形态对弯道交汇水流结构的影响在交汇区下游断面较明显。

A three dimensional numerical model is employed to calculate the flow structures in confluent main bend channel. The free surface is described by the rigid-lid approximation, and κ-ε turbulence mod- el is based on renormalized group （RNG）. The numerical model was tested by comparison with experimen- tal results, and the results show good agreement with test data. At different junction angel, the effect of the different shape of cross-section on flow structures is studied in confluent main bend channel. The re- sults show that the number of flow circulation on the channel with compound cross section is more than that of the V-shape section. The influence of different junction angle on flow structures in both kinds of cross-sections is obvious at confluence area and its upstream. But downstream of the bend, the influence of different junction angle on flow structures in V-shape cross-section is obvious and nearly invariable in compound cross-section. Therefore, the effect of the shape of cross section on flow structures in confluent main bend is obvious downstream of the channel.