移动下击暴流作用下高层建筑风荷载特性研究

为研究移动下击暴流作用下高层建筑的风荷载特性,采用可移动的冲击射流装置对高层建筑模型进行了测压试验,并通过计算流体力学方法进行数值模拟,分析了风暴移动过程中,风场中不同位置的高层建筑模型表面风压分布特性及风荷载作用机理。结果表明:风暴的移动会使风暴前缘风速加强,而使后缘风速减弱,从而使建筑表面的整体风压出现相应变化。当建筑位于风暴移动中心线上时,气流分离形成的漩涡主要出现在顶面迎风侧前沿及侧面迎风侧上角部区域,这些区域负压相对较大;建筑顶面在风暴经过时会产生较大正压。当建筑位于风暴移动中心线外时,高层建筑的来流风风向会随风暴的移动而不断发生变化;当建筑位于风暴前缘时,与来流风夹角较小的侧面会由于气流在钝体边缘的分离作用而出现较大的负压区域;当建筑位于风暴后缘时,建筑顶面角部区域会由于锥形涡的产生而出现较大负压。

Wind load characteristics of tall buildings under moving downburst

Here,in order to study wind load characteristics of tall buildings under moving downburst,a pressure-measuring test was conducted for a tall building model by using a movable impinging jet device,and numerical simulation was performed by using computational fluid dynamics(CFD)method.Distribution characteristics of wind pressure on surface of the tall building model at different locations in wind field and the action mechanism of wind load during wind storm moving were analyzed.The results showed that movement of storm can strengthen wind speed at storm front and weaken wind speed at storm trailing edge,so the overall wind pressure on building surface can change accordingly;when the building is located at center line of storm movement,the vortex formed by airflow separation mainly appears in front of windward side of the top surface and the upper corner field of windward side of lateral surface,and the negative pressure in these areas is relatively larger;when storm passes by,the top surface of building can produce larger positive pressure;when building is located outside storm moving center line,the incoming wind direction of building can change with storm movement;when building is located at the front edge of storm,the side with a smaller angle with incoming wind can have a larger negative pressure area due to separation of airflow at the edge of a blunt body;when building is located at the rear edge of storm,the corner area of the top surface of building can have a larger negative pressure due to the generation of conical vortex.