锥形涡诱导下建筑物顶面风荷载

通过风洞模拟实验，研究了在锥形涡诱导下建筑物顶面风荷载的特性. 针对一个立方体形模 型，给出了在不同风向角下压力分布的系统结果，进而分析了产生这样结果的原因和流动机 理，以及建筑物顶面的分离流动结构随风向角改变而改变及其演化过程，并指出锥形涡的出 现是建筑物顶面局部出现峰值负压的主要原因. 实验结果还显示，在一定风向角下，由于分 离流动产生的锥形涡结构在屋顶局部可以诱导出时均负压峰值达$-1.0$以上；在风向角 $\beta =30^\circ$时，锥形涡强度达到最大，其诱导的顶面附近局部时均负压峰值可 达$-2.4$, 瞬时风压达$-5.7$以上，是导致建筑物屋顶在强风下损坏的根本原因.

CONICAL VORTEX INDUCED WIND LOADING ON THE ROOF OF A BUILDING

By means of wind tunnel simulation the wind loading on the roof of building induced by conical vortex is investigated. The pressure distributions on the roof of the model are obtained and the mechanism of the flow is analyzed. The structure of separated flow from the roof of building is shown to vary with wind directions and its developing process is also analyzed. It is indicated that appearance of conical vortex is the main reason of occurrence of the peak suction on the roof. Results show that under certain wind directions the local time mean pressure coefficients are greater than $-1.0$. Moreover, the intensity of conical vortex reaches the maximum value at the wind direction $\beta =30^\circ$ and the time-mean peak suction and fluctuating coefficients may reach $-2.4$ and $-5.7$, respectively. It is usually the main cause of damage for the roof of buildings during strong winds.