开阔地貌台风风场现场实测与风洞试验应用研究

Field measurement and wind tunnel test application research of typhoon wind field in open terrain

基于100m高测风塔上风速仪的现场实测数据,获得了开阔地貌台风风场的平均风速剖面与湍流度剖面模型。在大气边界层风洞中准确模拟了台风风场和《建筑结构荷载规范》(GB 50009—2001)规定的B类风场,并通过一个大跨刚性模型测压试验,详细分析与对比了两类风场条件下大跨屋面风荷载分布规律特征。研究结果表明:在开阔场地条件下,台风近地边界层平均风速沿高度分布符合对数律,亦满足指数律,风剖面幂指数介于规范规定的A类风场与B类风场之间,平均湍流度比B类风场规定值大1倍;台风风场作用下,开阔地貌大跨结构屋面风荷载受湍流度的影响远高于受平均风速剖面的影响,体型系数随湍流度的增大而增大,屋面风荷载亦随之增大。

Models of mean wind speed profile and turbulence intensity profile of typhoon wind field for open terrain were obtained based on the filed measurement data recorded from anemometers installed on a 100 m height meteorological tower.The typhoon wind field and that of terrain category B specified in Load code for the design of building structures( GB50009—2001) were accurately simulated in a atmospheric boundary layer wind tunnel respectively, and then the characteristics of wind loads on a large-span roof structure based on the wind tannel tests with a rigid model were analyzed and compared. The results reveal that the vertical distribution of mean wind speed over open terrain in the surface boundary layer can be well described by a logarithmic profile and power-law profile,and the value of the exponent of the power-law profile is between that stipulated in the load code for terrain category A and B. The average values of the turbulence intensity observed during the typhoon wind are two times as high as those proposed by the design code of terrain category B.The effect of turbulence on wind pressures for the large-span roof is more significant than that of the mean wind speed profile. The shape coefficients of the building structure increase with the increase of the turbulence levels. The wind pressures acting on the large-span roof also increase.