山区桥址处CFD计算域的选取方法

Method of setting up the wind field of a mountain bridge site

山区桥址处风场具有较强的随机性与不确定性,在选取其CFD计算域时,盲目参考已有的工程可能会造成较大的模型误差,或增加大量的计算开销。为解决该问题,提出了山区复杂地形CFD计算域选取的方法与步骤,验证了其准确性。具体方法为:设置一个大范围的基准计算域进行初算,通过后处理软件绘制平均风压系数极差随高度的变化曲线、壁面附近水平面上的静压偏差等值云图以及横风向各平面静压值与对应边界面的均方根差值曲线,分别筛选出基准计算域在高度方向、顺风向及横风向上对整体风场贡献可忽略的区域,余下部分则可用于该区风场的求解。

The wind field of a mountain bridge site always shows a strong randomness and uncertainty. As a result, setting up its computational domain in CFD simulation by a simply reference to the existing experience causes a large amount of model errors and huge additional computational overhead. To solve this problem, a method to the selection of CFD computational domain of complex terrains is explored and verified. To start the procedure, a large reference computational domain should be chosen and preliminary solved. Then, its solution should be post-processed to draw the following curves or contour images： range of mean pressure coefficient align with height, static pressure deviation contour of the horizontal plane near the top of the bottom surface, the root-mean-square error of the static pressure of the crosswind planes compared to the corresponding edge surface. According to these curves and contour images, areas parts which have slight contribution on the overall wind field are figured out and abandoned, and the selected computational domain is constitutive of the rest parts of the reference domain.