考虑龙卷风作用方位效应的矩形结构屋面风压分布研究

Study on wind pressure distribution of the rectangle structure roof in consideration with the orientation effect under tornado action

不同于常规风,龙卷风是极强的小尺度系统,其作用方位的变化对结构表面的风压分布有一定的影响。为深入研究这种影响,本文采用CFD数值技术,假定结构处在龙卷风的移动路径上,模拟龙卷风以四种不同的方位角(0°,30°,60°,90°)作用于结构,得到结构屋面风压的分布状况。研究发现:各工况下屋面均表现出较强的吸力效应;并对16种工况进行整理得到两种分压分布形式(分布Ⅰ、分布Ⅱ),根据分布规律提出了屋面分区的建议方法。从所得分区风载体型系数值可看出是明显区别于现行结构风荷载规范中的取值,说明重要结构的抗龙卷风设计是非常必要的。

Unlike the conventional wind,the tornado is a strong but small-scale system. Changing the tornado acting orientation will have some impact on the wind pressure distribution of the structure surface. In order to study this effect,by assuming that the structure is in the movement path,the CFD numerical simulation technology is adopted to simulate the tornado acting in four different orientation angles（ 0°,30°,60°,90°）. It is found that,the roof shows strong suction effect under all working conditions,two kinds of wind pressure distribution types（ distribution Ⅰand distribution Ⅱ） are obtained by arranging the 16 working conditions,and the suggestions for roof zoning are put forward in accordance with the distribution law. The wind load shape coefficient for each sub-region of the roof can be seen to be significantly different from the value of current structure wind load specification,which shows that the antitornado design is very necessary for the significant structure.