半月拱形大跨度屋盖的脉动风压特性研究

The effect of openings on a half-moon-shaped long-span roof stadium

对某半月拱形大跨度屋盖体育场进行了刚性模型的风洞试验,对该体育场屋盖的脉动风压、非高斯分布及脉动风压谱在开孔前后的变化情况进行了详细研究。基于偏峰态检验法和斜度峰态统计量,得到半月拱形屋盖非高斯区域划分标准为|S|>0.4或|K|>3.5。采用FPE、AIC定阶准则确定了功率谱的阶数p取40,并得到开孔前后功率谱的变化曲线。得出以下主要结论:开孔能有效减少脉动风压系数值较高区域的脉动风压系数值,削减率在30%~55%之间,但对脉动风压系数值较低的区域影响小;在开孔后,脉动风压系数值较高的区域由原先的非高斯分布改变为高斯分布。由于屋盖非高斯区在特征湍流作用下产生气流分离区,使该区域后缘受湍流作用影响产生小尺度漩涡,开孔能改变主导气流的漩涡尺度,减少特征湍流的影响;而高斯区由于湍流特征作用弱,开孔产生的影响不明显。

To investigate changes of the fluctuating wind pressure distribution,non-Gaussian distribution and fluctuating wind pressure spectrum of stadium roof with and without hole openings,rigid model wind tunnel tests of a half-moon-shaped long-span roof stadium were carried out.Based on the skewness and kurtosis test method and statistics of skewness and kurtosis,the criteria for dividing the non-Gaussian region of the half-moon-shaped roof can be obtained as follows:|S|>0.4 or|K|>3.5.The estimated order p=40 of the power spectrum function is discussed by FPE criterion and AIC criterion and the curve of power spectrum before and after opening is obtained.Main conclusions are drawn as follows:Hole openings can effectively reduce pulsating wind pressure in area with higher coefficient values of pulsating wind pressure,and the reduction rate is between 30%and 55%,but it has little effects on area with lower coefficient of pulsating wind pressure.Region with higher coefficient of pulsating wind pressure changes from original non-Gaussian distribution to Gaussian distribution after holes were opened.Because body-induced turbulence in the non-Gaussian region of the roof produces the airflow separation region,the trailing edge of the region is affected by the turbulence and generates a small scale vortex.Hole openings change vortex size of dominant airflow and reduce the influence of characteristic turbulence.However,due to weak turbulence characteristics in the Gaussian region,the effect of hole openings is not obvious.