考虑地貌影响平屋面低矮建筑屋面局部风压特性试验研究

Wind tunnel test of wind pressures around roof local area on flat roof low-rise building under terrain

基于缩尺比为1∶20的平屋面低矮房屋风洞试验模型,在A、B、C三类不同地貌条件下,以风向角为变量,研究地貌对低矮建筑屋面局部平均、脉动以及极值风压分布的影响。试验结果表明:屋面局部区域受风向角影响较大并呈现一定规律性。迎风屋面边沿区域以及角部区域受风向影响最为明显且风压大于其他区域;在斜风向45°风向角时,迎风屋面边沿区域角部测点平均、脉动、极值风压系数最大,为该类房屋最不利风向角;不同地貌对低矮房屋屋面平均风压系数影响较小,对脉动、极值风向系数影响较大。在0°、90°风向角时迎风屋面边沿平均风压系数受地貌影响较大,在斜风向下地貌的改变对屋面平均风压系数影响不大;随湍流度的增大屋面平均、脉动、极值风压系数绝对值也相应增大。

Based on the wind tunnel test of a 1∶ 20 scaled low-rise building with flat roof,the effects of wind angles and terrain on the mean,fluctuating and peak wind pressures on local area of the flat roof of low-rise building under classes of A,B and C terrain are researched. Wind tunnel test results show that the characteristics of wind pressures at local area are significantly influenced by wind directions and exhibit some regularities. The wind pressures on windward roof edges and corner regions of the flat roof of low-rise building are evidently higher than other regions. In oblique wind directions,the mean,fluctuating and peak wind pressures on local area of the flat roof of low-rise building are largest which is the most unfavorable wind angle. The different terrains have little effect on mean wind pressures on the flat roof of low-rise building. However,it has a great influence on fluctuating and peak pressure coefficients and mean wind pressures around the areas of windward roof edges under at wind angle of 0°and 90°. But it has little influence on oblique wind directions. The mean,fluctuating and peak pressure coefficients will also increase with the turbulence intensity.