大跨度柱面网壳结构风荷载特性风洞试验研究

Experimental study of wind load characteristics on large-span cylindrical latticed shell

为研究大跨度柱面网壳结构受特征湍流影响的风荷载特性,在大气边界层风洞中对一大跨度柱面网壳干煤棚结构进行刚性模型同步测压试验,获得了结构表面测点在36个风向角下的测压数据。根据测试结果分析了结构的平均、脉动风压分布特性,脉动风荷载谱以及测点间脉动风荷载的相关性等。结果表明:结构在不同风向角下,特征湍流的影响情况不同,平均风压和脉动风压最大值出现的位置和范围存在较大差别;结构迎风位置测点脉动风荷载无量纲功率谱数值较大,且频谱成分复杂,随着气流向尾流区域发展,无量纲功率谱谱峰宽度及对应的无量纲频率具有增大的趋势,且高频段的衰减速度变缓;测点间脉动风荷载相关性随着频率及测点间空间距离的增加而减小,当频率达到30 Hz时,其相干函数值快速衰减,可以近似认为不相关。

To investigate wind load characteristics influenced by signature turbulence on large-span cylindrical latticed shell,a synchronized pressure test on a rigid model of large-span cylindrical latticed shell was conducted in a boundary layer wind tunnel. The mean wind pressure,fluctuating wind pressure,power spectrum and correlation of fluctuating wind load were studied based on the test results of 36 wind directions. The results show that at different wind angles,the signature turbulence influence varies greatly. Therefore,the location and range of the maximum value of both mean and fluctuating wind pressure are also different. The power spectrum of fluctuating wind load is larger on the windward side,and the spectral components are more complicated. With the airflow extending to the wake wind region,the peak band and the corresponding dimensionless dominant frequency of the power spectrum are increasing, and the attenuation rate of power spectrum in high frequency domain are slowing down. In addition,the fluctuating wind load correlation decreases with the increase of both frequency and the distance between pressure measuring points. As the frequency reaches 30 Hz,the value of the coherence function between measuring points attenuates rapidly,and tends to be zero,therefore,in this case it can be approximately considered uncorrelated.