基于风噪声物理声学理论的高层建筑风压脉动预测与实测研究

This project applies the wind noise physical acoustics approach to the study of the wind pressure fluctuations acting on high-rise buildings. Despite of the rapid progress in the field of wind engineering research in recent years, there is a lack of study on the fundamental theory of the wind action mechanisms. The engineering study is in need of scientific theories' promotion and guidance. Currently most of the wind pressure fluctuations research related to atmospheric boundary layer was conducted in a wind tunnel; there has been a limited number of study conducting experimental investigations directly in the atmospheric environment. Particularly, the current understandings of the wind pressure fluctuations characteristics at the infrasonic frequencies under real atmospheric conditions are insufficient, yet it may be well related to the wind induced oscillation and the comfortability of high-rise buildings. For the sake of the analysis above, this project introduces contents as follows: (1) Developing an analytical model for wind pressure fluctuations on high-rise buildings based on the current wind noise model for bluff body, and developing calculations of the wind pressure fluctuation spectrum from the turbulence spectrum and the wind velocity profile; (2) Conducting theoretical predictions and on-site measurements of the wind pressure fluctuations on the windward side of an ideal rectangular cylindrical high-rise building at different heights and under different wind conditions in real atmosphere; (3) Based on the combined theoretical and experimental results, analyzing the dependence relationships of the wind pressure fluctuations on high-rise buildings with respect to different parameters, developing understandings of the wind pressure fluctuations characteristics at infrasonic frequencies, and evaluating the related dB level in frequency-domain. We expect that this project will prove useful to a better understanding and prediction of the wind pressure fluctuations on high-rise buildings, as well as useful to a better understanding of and approach to the wind induced oscillation and comfortability issues.

本项目采用风噪声物理声学方法对高层建筑的风压脉动进行研究。尽管近年来风工程方面的研究发展迅速，风力作用的基础理论研究却非常缺乏，工程研究需要科学理论的推动和指导。目前对大气边界层的风压脉动问题研究多数在风洞中进行，大气中实测的研究开展的不多。特别是对次声频段的风压脉动在大气中的真实特性目前人们缺乏理解，但这一问题与高层建筑的风振和舒适性问题可能都存在紧密的联系。由上，本项目拟开展以下研究：（1）在现有钝体风噪声模型基础上发展高层建筑的风压脉动模型，由湍流脉动谱和平均风速剖面预测风压脉动谱；（2）对某理想矩形柱体高层建筑进行大气中不同风条件和高度处迎风面的风压脉动预测与实测研究；（3）结合理论预测与实测结果分析高层建筑的风压脉动随各种参量的变化规律，理解次声频风压脉动特性并在频域对分贝量级做出评价。本项目研究有助于对高层建筑的风压脉动的更好预测和理解，以及对风振和舒适性问题的更好认识和解决。

对大气边界层的风压脉动问题无论是理论上还是大气中实测的研究目前开展的不多。真实大气中次声频段的风压脉动与高层建筑的风振和舒适性问题存在紧密的联系。我们针对高层建筑的风压脉动和风振问题采用风噪声物理声学方法进行了深入研究。首先，我们在现有风噪声钝体静态作用压的理论基础上，引入湍流和平均风速的高度依赖关系，发展了高层建筑风压脉动谱预测模型；其次，建立了风速、风压和振动加速度数据同步采集测量系统，对某理想矩形柱体高层建筑进行了不同风条件下的大气中现场实测研究；最后，通过结合理论预测与实测结果分析高层建筑的低频风压脉动特性和影响因素，在频域对次声频分贝量级做出评价。研究发现大气稳定性影响低频风压脉动谱级，稳定的大气条件具有更高的低频风压脉动谱级，而地面粗糙度不影响低频的风压脉动谱。理论预测的风压脉动谱在低频随频率减小先达到峰值而后减小，且与实验测量结果吻合较好。对我国北方内陆城市近地风场特性进行了观测，通过对顺风向脉动风速和脉动风压数据分析发现建筑顺风向的脉动风速和脉动风压都不符合正态分布，说明城市近地风场不是严格的随机场。两者偏离趋势、偏离程度并不一致，春季脉动风速概率分布比正态分布陡峭，秋季脉动风速概率分布比正态分布平坦。在天气情况及风力级别接近的情况下，秋季风的脉动强度要远大于春季风。通过振动加速度响应测量发现了风力作用下建筑低频前两阶的平移振型和第一扭转振型，验证了对该建筑当风接近垂直入射时横风向响应大于顺风向响应的预测，并对该高层建筑抗风能力和风振舒适度做出了评价。