湍流积分尺度影响低矮房屋屋面风压特性风洞试验研究

采用缩尺比为1∶20的双坡屋面低矮房屋风洞试验刚性模型,以湍流积分尺度为变量,研究湍流积分尺度影响低矮房屋屋面局部区域平均、脉动、极值风压分布特征和变化规律。研究发现,湍流积分尺度的改变对平均风压系数影响不明显,对脉动、极值风压系数影响较大,且随湍流积分尺度的增大,屋面测点脉动、极值风压系数绝对值增大。当来流垂直于屋面长边时,在迎风屋面,距迎风屋檐越远,平均风压系数绝对值越小,山墙和角部区域脉动风压系数越小,而迎风屋面中心区域脉动风压系数越大。在背风屋面,远离屋脊测点的平均、脉动风压系数绝对值逐渐越小。双坡屋面低矮房屋在迎风屋檐及山墙区域风压相对较大,这些局部区域在强风作用下更易受到破坏。

Wind tunnel test research of wind pressures on roof of low-rise building under turbulence integral scale

A rigid wind tunnel test model of low-rise buildings with double slope roofs with scale ratio of 1 :20 was used to study the influence of turbulence integral scale on the local average, fluctuation and extreme wind pressure distribution characteristics and variation law of low-rise buildings. It is found that the change of turbulence integral scale has no obvious effect on the average wind pressure coefficient, but has great influence on the fluctuation and extreme wind pressure coefficient. With the increase of turbulence integral scale, the absolute values of the fluctuation and extreme wind pressure coefficient of roof measurement points increase. When the inflow is perpendicular to the long side of the roof, the farther away from the windward roof, the smaller the absolute value of the average wind pressure coefficient, the smaller the fluctuating wind pressure coefficient in the gables and corners, and the larger the fluctuating wind pressure coefficient in the central area of the windward roof. On the leeward roof, the mean and absolute values of fluctuating wind pressure coefficients, which are far away from the roof, are gradually smaller. Low-rise buildings with double slope roofs have relatively high wind pressure along windward roofs and gable areas, which are more vulnerable to damage under strong wind.