大跨度封闭式柱面屋盖脉动风荷载非高斯分布试验研究

Experiment study on non-Gaussian distribution of fluctuating wind load on long-span enclosed cylindrical shell roof

在大气边界层风洞中对一大跨度封闭式柱面屋盖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个风向角下的风压数据,根据测试结果对结构脉动风荷载非高斯分布规律及其形成机理进行了分析。通过对结构表面测点脉动风荷载概率密度分布曲线与标准高斯分布曲线对比分析,发现结构表面受特征湍流影响显著部位,其测点脉动风荷载非高斯分布特性比较突出;通过对测点间脉动风荷载相关性分析,发现特征湍流影响显著部位,大尺度漩涡不满足独立同分布,相关性较强,风压信号表现为非高斯特性。以试验研究为基础,通过测点脉动风荷载测试信号的斜度值和峰态值累积概率分布曲线,得到累积概率为80%对应的斜度值和峰态值,并以此为标准,划分了该柱面屋盖表面高斯与非高斯区域,发现不同风向角下,在迎风前缘来流撞击位置以及结构边角附近为非高斯区域,气流平稳位置为高斯区域。

Synchronized pressure tests on a rigid model of long-span enclosed cylindrical shell roof was conducted in a boundary layer wind tunnel,and measurements were taken for 36 wind directions.The non-Gaussian distribution characteristics and formation mechanism of fluctuating wind load were studied based on the wind load data obtained from the wind tunnel test.Firstly,the comparative analysis between probability density distribution of fluctuating wind load and standard Gaussian probability density distribution was done.The results show that the non-Gaussian distribution characteristics are relatively outstanding at the locations which are greatly influenced by the signature turbulence.Secondly,the formation mechanism of non-Gaussian distribution was discussed by analyzing the correlation of fluctuating wind loads between different taps.At the locations which are greatly influenced by the signature turbulence,the vortexes do not satisfy with the independent identically distribution,and are greatly correlated;as a result,the characteristics of non-Gaussian distribution are relatively strong.Finally,making use of the value of skewness and kurtosis which are corresponding to the 80% cumulative probability,the Gaussian and non-Gaussian zones of longspan enclosed cylindrical shell roof were divided.The results show that the wake area,corner area and the areas which are impacted by inflow belong to the non-Gaussian zone,and airflow-steady areas belong to the Gaussian zone.