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采用计算流体动力学计算方法,对不同平移速度的龙卷风作用下典型高层双坡屋面的风荷载进行了数值研究。综合滑移网格和动网格的各自优势,利用动网格法和滑移交界面分割技术,实现了等效移动龙卷风场的数值模拟。计算研究表明:龙卷风场作用下,各种坡角(0°、15°、30°和60°)的计算模型的屋面风荷载均为吸力,在距风场中心距离为最大切向风速所对应半径的附近,屋面吸力最大;在等效移动龙卷风场中,由于充分捕捉了龙卷风场作用于计算模型过程中的动态效应,屋面的吸力远大于其在静止龙卷风场中的吸力,30°坡角屋面吸力增幅最大(83.9%),0°坡角屋面吸力增幅最小(74.3%);在距风场中心距离为最大切向风速所对应半径的附近,出现了风压激增区,在此区域屋面的吸力急剧增大,等效移动龙卷风场中此现象更加明显。此外,龙卷风的风致破坏不仅与其风场强度正相关,而且与平移速度也大致呈正相关,计算模型屋面风压随平移速度的增大而增大,但当平移速度超过某限值(约为最大切向风速的25%),计算模型屋面风压略有下降。
The computational fluid dynamics (CFD) method is used to study the wind load of a typical high-rise double-dip roof under the action of tornado with different translational velocities. Based on the respective advantages of sliding grid and moving grid, the numerical simulation of equivalent moving tornado field is realized by using moving mesh method and sliding interface segmentation technique. Computation studies show that roof wind load of various slope angles (0 °, 15 °, 30 ° and 60 °) is suction under the action of tornado field, and the distance from the wind center to the maximum tangential wind velocity In the equivalent moving tornado field, due to fully capturing the dynamic effect of the tornado field acting on the calculation model, the suction force of the roof is much greater than that of the suction force in the static tornado field, and the 30 ° sloping angle housing The maximum increase of surface suction (83.9%) and the smallest increase of suction at 0 ° (74.3%); near the radius corresponding to the maximum tangential wind speed, the wind pressure surge area appeared. In this area, Of the suction increased dramatically, the phenomenon of moving the tornado equivalent to more obvious. In addition, the wind damage of tornadoes is not only positively correlated with the wind field intensity, but also with the translational velocity, and the wind pressure of the model roof increases with the increase of the translational velocity. However, when the translational velocity exceeds a certain limit Large tangential wind speed of 25%), calculate the model roof pressure slightly decreased.