基于CFD的单个建筑物风场模拟参数选择

运用流体力学软件FloEFD对沽源单个建筑物周围的风场进行数值模拟。通过不断改变模型中计算参数的设置进行一系列模拟试验,对比模拟试验结果,并与观测资料进行比较,分析不同计算参数对模拟结果的影响,并获得适用于该模型的最佳参数。主要研究的计算参数包括计算域高度,初始网格等级,局部初始网格等级和不同平均风速剖面形式。结果表明:计算域高度从3倍建筑物高度开始,空腔区的长度、漩涡中心位置以及再发展区的边界位置基本保持稳定。随着初始网格等级的增加,空腔区的长度、再发展区的边界位置及计算时间逐渐增大。局部初始网格等级对模拟结果影响不显著。以两种不同平均风速剖面形式进行模拟,迎风漩涡长度不同,背风面影响不大。与观测资料比较显示,最优参数组合为:计算域高度为3倍建筑物高度,初始网格等级为4、局部初始网格等级为4、平均风速剖面形式为指数律。

Parameters Selection in CFD Based Wind Field Simulation for an Isolated Building

A CFD model （FloEFD） is applied to the wind field simulation around an isolated building in the Guyuan County Experiment Site. To obtain the optimal parameters of the model, a group of sensitive numerical experiments with different model parameters are carried out. The cavity length, vortex center, and the boundary location of the redevelopment area are used as the indexes to assess the outcomes. The results show that all the indexes are stable basically if the height of the computational domain is greater than 3h （the height of the building）. The values of the indexes increase with the increasing levels of the initial mesh. All the indexes are not sensitive to the levels of local initial meshes. The vortex length before the building is more sensitive to the form of the mean wind profile than that after the building. By comparing to the observing data, the optimal parameters are： the height of computational domain being 3 times as high as building height, the level of the initial mesh being 4, the level of the local initial mesh being 4 and the form of mean the wind profile being exponential.