摘要
为研究湍流积分尺度对高层建筑风荷载大小和分布的影响,研究其合理取值,基于大涡模拟开展了B类地貌不同湍流积分尺度下CAARC(commonwealth advisory aeronautical research council)标准高层建筑模型绕流模拟,并将模拟结果与风洞试验进行了比较.研究结果表明:大涡模拟能较好地反映高层建筑周围风场绕流特性和表面风压分布.随着湍流积分尺度的增大,平均运动的变形率向湍流脉动输入能量,以致平均风速降低、湍流强度增大;侧面风压脉动性降低15%、分离流附着提前出现;基底扭矩谱和弯矩谱的峰值及高频段幅值均减小;层斯托罗哈数在0.4倍建筑高度以下基本相同,随高度的增加其值下降20%~30%;层平均阻力系数下降5%~10%;迎风面风压系数平均值下降2%~5%,侧面和背面下降12%~17%.湍流积分尺度对迎风面和侧面上风向的风压水平相关性、层升力和0.8倍建筑高度以下的层阻力相关性的影响可以忽略.随湍流积分尺度的增大,风压水平相关系数增大,背风面增大5%~10%,侧面下风向增大15%~25%,0.8倍建筑高度以上层阻力相关性系数增大25%~50%.B类地貌湍流积分尺度的调整系数为0.4时,计算得到的风荷载与试验结果趋于一致.
To investigate the influence of turbulence integral length on the wind pressure value and distribution on the surface of tall buildings and determine the reasonable value of turbulence integral lengths,a large eddy simulation（ LES） was conducted under different turbulence integral lengths to represent the wind flow field around the commonwealth advisory aeronautical research council（ CAARC） standard tall building model in exposure category B. The obtained results were compared with those from the wind tunnel test. It is found that the LES is a feasible tool to represent the wind flow around a high building and the distribution of wind pressure on the building surface. It is also found that with the increase in the turbulence integral length,the energy of turbulent fluctuation increases,resulting from the deformation of flow average movement; the mean wind speed will decrease,and hence,the turbulence intensity will increase. It is also found that the fluctuation of windpressure decreases by 15% on the side face,while the reattachment point of separated flow moves forward. Meanwhile,the local peak at the high-frequency range as well as the peak of aerodynamic base moment and torque spectrum decrease. While the Strouhal number of the layer is essentially the same at a height lower than 0. 4 times the height of the building,it decreases by 20%-30% with the increase in height,and the drag coefficients of the mean layer decrease by 5%-10%. The results also show that the mean coefficients of the wind pressure in the windward side reduce by 2%-5%,with a decrease of 12%-17% in the crosswind side and leeward side. The investigation further finds that the turbulence integral length has minor effects on correlations of horizontal wind pressure in the windward side and crosswind side in the upwind direction,and the lift on the layer and drag on the layer at a height less than 0. 8 times the height of the building. With the increase in the turbulence integral length,the correlation coefficient of the horizontal wind pr
作者
祝志文
邓燕华
ZHU Zhiwen;DENG Yanhua(College of Civil Engineering,Hunan University,Changsha 410082,China)
出处
《西南交通大学学报》
EI
CSCD
北大核心
2018年第3期508-516,共9页
Journal of Southwest Jiaotong University
基金
国家自然科学基金资助项目(51278191)
国家重点基础研究发展计划资助项目(2015CB057702)
