下击暴流作用下低矮建筑风荷载大涡模拟

采用大涡模拟方法，研究非稳态雷暴风作用下低矮建筑的风荷载特征，分析下击暴流的不同发展阶段中建筑物所在的径向位置、屋面坡度和风向角等参数对建筑风荷载的影响. 结果表明：下击暴流各发展阶段风荷载效应差异显著，当气流冲击地面后形成的首个环形涡掠过建筑时，建筑表面风荷载最大；当建筑物处于不同径向位置时，环涡经过建筑物形成的瞬态风压与同样位置处稳态射流作用下的风压差异较大；屋面坡度对迎风面风压系数分布影响较小，但对迎风侧屋面风压系数分布的影响非常显著，随着屋面坡度的增大，迎风屋面风压系数由负值逐渐变为正值；建筑物迎风前沿角部区域的风压系数受风向角的影响较为明显，在所测试的工况中，风向角为45°时影响最为显著.

Large eddy simulation of wind load on low-rise buildings subjected to downburst

The large eddy simulation method was used to study the wind load characteristics of low-rise buildings under the action of unsteady thunderstorms. The following aspects were analyzed to study the influence on the wind load of the building in different development stages of the downburst: the radial position of the building, the roof slope and the wind direction angle, etc. Results show that there are significant differences in wind load effect at different development stages. When the first ring vortex generated by the airflow hitting the ground blows over the building, the wind load of the building is the most unfavorable. While the building is in different radial positions, the transient wind pressure caused by the ring vortex passing through the building is quite different from that caused by the steady downburst at the same position. The slope of roof has less influence on the distribution of wind pressure coefficient in the windward roof, but great influence on that in the windward side roof. When the slope of the roof increases, the wind pressure coefficient of the windward roof gradually changes from negative value to positive value. The wind pressure coefficient for the corner of the windward front of the building is obviously affected by the wind direction angle. In the tested condition, the influence is most significant when the wind direction angle is 45°.