基于时变边界屋面积雪分布数值模拟

为了预测风作用下屋面积雪的分布,采用Euler-Euler两相流混合模型,结合最新改进的k-ω模型等数值方法开发分析程序,对风致屋面积雪分布进行了数值模拟.模拟中为考虑积雪对屋面绕流的影响,计算区域边界根据雪深变化采用时变边界.对一典型阶梯形屋面积雪分布进行数值模拟,获得了几种不同状态下屋面积雪分布的时间历程.模拟结果表明:随着时间的发展,屋面积雪分布对屋面绕流产生较大影响,屋面积雪沉积率随之发生变化;模拟时长22 h的计算结果与实测结果基本一致,不考虑积雪对屋面绕流的影响将产生较大误差;不同风速比下模拟的屋面雪深分布形态基本一致,但入流风速比越小,雪深分布系数相对越大,达到近似分布的模拟时间就越短. 

Numerical Simulation of Wind-Induced Roof Snow Distributions Based on Time Variable Boundary

In order to predict snow deposition on a building roof under wind action, a numerical method based on the Euler-Euler two-phase mixture model was employed to simulate wind-induced roof snow distributions. In the method, the latest improved k-ω turbulence model is used to turbulence closure, and the computational domain boundaries uses the adaptive deformation technique based on snow depth changes. An example of numerical calculation was given to verify the validity of this method, and then snow distribution on a stepped roof was simulated. The time histories of roof snow distributions in some different states were gained. The simulation results show that along with the time development, the snow distribution on the roof has a great influence on air flow, and the snow deposition rate will change. The simulation results after 22 h are in good agreement with the field observation ones, and without considering snow effect on air flow, large errors will be result in. The simulation results for different velocity ratios are basically consistent. As the velocity ratio is smaller, the snow-depth coefficient gets larger, and the simulation time of reaching similar distribution becomes shorter.