山区公路桥涵消能防冲三维数值模拟

Three-dimensional Numerical Simulation of Energy Dissipation and Erosion Control at Mountainous Highway Bridges and Culverts

以k-ε湍流模型封闭Reynolds方程,采用VOF法追踪自由表面及SIMPLE算法求解方程组,对山区公路桥涵的常用消能方式及两种设计方式(波浪式、挑流式)进行了三维数值模拟。结果表明,常用式的消能率最小,底流速值最大,下游回流影响区域比较大;波浪式消能率大于常用式,但下游水流存在顶冲现象,形成了不规则、大区域的横轴漩流;挑流式消能率最大,底流速值最小,下游回流影响区域小于前两种消能方式,流速分布相对均匀,是桥涵比较合理的消能防冲方式。

With software FLUENT,the energy dissipation and erosion control of three kinds of highway bridges and culverts are simulated by the 3-D numerical model,in which a k-ε turbulent model is used to simulate close Reynolds equations and the volume of fluid（VOF） method is used to track the free water surface.Results show that commonly used type of energy dissipation is small flow downstream effects but large area backflow.Waving is better than common energy dissipation,but water has a rush down stream on the downstream,forms an irregular and large area distribution whirl;deflecting flow type has an obviously effect ion,bottom velocity is smaller than the previous two types,the reflux influence area on downstream is small and velocity distribution is relatively uniform,therefore,deflecting flow type is a better type of energy dissipation and erosion control.