高拱坝表孔宽尾墩流道内水流特性的数值模拟研究

Study on Numerical Simulation of 3-D Flow Formed by Flaring Gate Pierson Surface Spillways in High Arch Dams

宽尾墩应用于高拱坝表孔后,其下泄水流的空中扩散特性与宽尾墩流道内的水流特性密切相关。采用k-ε双方程紊流模型对宽尾墩应用在高拱坝坝身泄洪表孔时的水流特性进行了3维数值模拟,给出了孔流道水面线、压力、流场等水流特性。计算值与模型试验值对比,两者吻合较好。计算结果发现,坝面中线压力分布与侧墙压力分布存在相似规律,所不同的是侧墙压力在宽尾墩转折点位置存在局部增大;墩尾压力分布受墩内水流流线弯曲影响,其分布不再符合净水压力分布规律;墩尾水流流速大小沿水深方向变化不大,但流速方向变化比较明显。

When flaring gate piers are on surface spillways in high arch dam, the dispersion of plunging jets from surface spillways is closely related to the charateristics of flow. The k - ~ two-equational model for turbulent flow is applied to numerically simulate the 3-D flow to find out the characters. The results of numerical calculations are in good agreement with those of model test and shows that the pressure distributions on middle line and sidewalls show similar behaviours, but the difference is that the pressure of sidewalls has local increasing near the turning point of the flaring gate piers. Because of the influence of streamline curving in flaring gate piers, the pressure distribution of end parts of flaring gate piers does not agree with the law of pressure distribution in still water. It is also found that velocity of flow change varies little along the depth, but the vector of velocity changes apparently.