典型双坡低矮建筑屋面局部风压非高斯特性研究

针对坡角为18.4°的典型双坡低矮建筑屋面局部风压非高斯特性,在A、B、C 3类地貌下展开了风洞试验研究。主要研究了典型测点风压系数时程概率密度的分布特征,分析了不同地貌类别和不同风向角下风压非高斯区的分布规律,探讨了风压非高斯特性与屋面流场的关系。结果表明:斜风向下,相比Gaussian分布和Lognormal分布,GEV分布和Gamma分布能更好地拟合屋面易损区的风压系数概率分布,但当偏度与峰度较大时,对长拖尾区域的拟合效果较差;地貌类别和风向角对低矮建筑屋面风压非高斯区分布影响显著,斜风向下风压高斯区沿来流方向分成三股区域,且随着地貌类别变化而沿来流方向移动;屋面风压非高斯特性与风压空间互相关性系数呈正相关。

Research on Non-Gaussian Features of Local Wind Pressure for Typical Low-Rise Building with Gable Roofs

In view of the non-Gaussian characteristics of local wind pressure on the typical low rise building with a slope angle of 18.4°, a wind tunnel test has thus been carried out under the landforms of A, B and C. A research has been carried out on the distribution characteristics of time history probability density of wind pressure coefficient at typical measuring points, followed by an analysis of the distribution laws of non-Gaussian area of wind pressure under different geomorphic categories and wind directions, with a discussion of the relationship between non-Gaussian characteristics of wind pressure and roof flow field. The results show that, compared with Gaussian distribution and lognormal distribution, GEV distribution and gamma distribution can better fit the probability distribution of wind pressure coefficient in the vulnerable area of the roof, but the fitting effect of long trailing tail area is undesirable with a large skewness and kurtosis; the type of landforms and wind direction angle have significant influence on the non-Gaussian distribution of wind pressure of the low building roof. At the oblique wind direction, the Gaussian wind pressure area is divided into three sections along the direction of incoming flow, along which the area moves with the change of terrain categories. The non-Gaussian features of wind pressure is positively related to the mutual correlation coefficient of wind pressure space.