基于大涡模拟的超高层建筑风振响应分析

Wind-induced response analysis of super high-rise building based on large eddy simulation

计算风工程作为风洞试验的补充技术,已得到越来越多的应用,但是使用RNS方法进行非定常计算精度低,而大涡模拟可对大尺度漩涡直接求解,可以得到较精确的模拟结果。因此对超高层建筑进行了多工况的CFD大涡模拟,研究不同风向角下建筑表面风荷载的变化规律,并与风洞试验结果进行对比,简要阐述了建筑体型对风荷载的影响。将大涡模拟得到的非定常风压时程作为结构激励,采用频域法计算高层建筑的随机振动响应,根据惯性风荷载方法,求解结构的等效静力风荷载,并与风洞试验结果进行对比。对比分析表明,大涡模拟技术可以很好地模拟建筑表面风荷载,并可以克服测点布置、不同步测试带来的系统误差;频域法分析得到的等效静力风荷载与风洞试验结果基本一致,可以将本文方法计算得到的风荷载作为设计依据。

Computational Wind Engineering（ CWE） as a complement to wind tunnel test has been more and more applied.Although the accuracy of unsteady RNS calculation is very low,large eddy simulation（ LES） can directly solve large-scale vortices. It is easy to get more accurate simulation results. A series of LES by CFD of high-rise building were carried out to study the changing rule of wind loads at different wind angles. The wind tunnel test results and numerical simulation results were compared to explain the effects of building shape. To calculate the random vibration response of high-rise buildings,frequency domain method（ FDM） was implemented. And the unsteady wind pressure time-history data which were obtained from LES was used as structural loads. Based on structural response and the concept of inertial wind load,the equivalent static wind load（ ESWL） can be calculated which was compared with wind tunnel test results. Comparative analysis shows that the wind load can be accurately obtained from the LES which can overcome some systematic errors caused by measuring points and non-simultaneous testing. And ESWL based on LES and FDM is basically identical with that obtained from wind tunnel test,which,therefore,can be used as wind loads for design.