湍流边界层中低矮建筑绕流大涡模拟  

Large eddy simulation of flow around a low-rise building immersed in turbulent boundary layer

作　　者：朱伟亮[1] 杨庆山[1] 

机构地区：[1]北京交通大学土木工程学院,北京100044

出　　处：《建筑结构学报》2010年第10期41-47,共7页Journal of Building Structures

基　　金：国家自然科学基金重点项目(50938008);国家杰出青年基金项目(50725826)

摘　　要：通过对平板湍流边界层进行大涡模拟,采用拟周期边界条件维持湍流边界层厚度稳定,提取速度和压力时程作为低矮建筑绕流模拟之脉动入流边界条件,研究脉动入流下的低矮建筑绕流特性。研究结果表明：入流边界特性对网格变化适应性良好,其平均速度剖面、湍流强度、流速频谱特性基本符合空旷地貌风场特性;脉动入流下,建筑表面的平均风压系数、脉动风压系数的计算结果与风洞试验结果基本吻合。受雷诺数及湍流强度的影响,流动分离区负压与试验值存在一定差别;屋盖上分离区风压时程具有非高斯概率特性,尤以气流分离较剧烈的屋盖迎风边缘及屋盖两侧风压的非高斯特性明显,该特征与风洞试验基本一致;受非高斯特性的影响,建议峰值因子g取4.5~5.5。A turbulent boundary layer developed on the flat plate was simulated using large eddy simulation,and a quasi-periodic boundary condition was used to keep boundary layer thickness constant.Velocity and pressure history were extracted from the turbulent boundary layer and were set as the inflow condition for the flow simulation around a low-rise building,flow and pressure characteristics under turbulent inflow were studied.The results show that the properties of turbulent inflow can be well preserved in non-uniform grid system.Velocity profile,turbulent intensity and spectrum properties of the inflow are similar with those of wind field on open area.Mean and fluctuating pressure coefficients on building surface are basically in agreement with wind tunnel test,except for the flow separation regions,which could be attributed to discrepancy of the turbulent intensity and Reynolds number between present simulation and wind tunnel test.The pressure on the roof shows non-Gaussian property,especially in flow separation region,such as windward edge and side edge.The non-Gaussian properties are in good agreement with wind tunnel test.Due to the pressure non-Gaussian properties,higher peak factors are recommended when predict gust pressure on the roof,the value of g=4.5-5.5 are recommended.

关 键 词：低矮建筑 结构抗风 大涡模拟 脉动入口 风压系数 

分 类 号：TU312.1[建筑科学—结构工程] TU311.41