【摘要】 为了研究下击暴流的风场特性及其对建筑物的作用，文章采用雷诺时均NS方程(Reynolds-averaged Navier-Stokes equations, RANS)模拟下击暴流风场，在最大风速位置和来流风垂直于建筑立面情况下，对凹型、T型、L型3类异型低矮建筑内外表面所受风压的分布特点进行研究，并与立方体型建筑对比，重点分析立面洞口设置方式对风压分布的影响。结果表明：对于3类异型建筑，洞口位置变化对外表面风压系数影响较小，对内表面风压系数影响较大，其中迎风面开洞对内表面风压系数分布影响最显著，而穿堂风是导致内表面风压系数降低的主要原因；当前后两面开洞时，迎风面居中靠近洞口上、下缘位置风压系数存在骤增和骤减现象，凹型建筑洞口上、下缘风压系数差值最大，为0.288,而T型建筑洞口上、下缘风压系数差值最小，为0.137;凹型、L型建筑5种洞口模式之间迎风面横向中线处风压系数差异较小，而T型建筑5种洞口模式下该处风压系数差别较大；与封闭模式相比，单面开洞时，凹型、T型和L型建筑屋面内外风压合力下合风压系数增幅最大，分别为348.6%、493.6%、250.7%。更多还原

【Abstract】 In order to study the wind field characteristics of downburst and its effect on buildings, Reynolds-averaged Navier-Stokes equations(RANS) method, which solved N-S equation with renormalization group(RNG) k-ε turbulence model, was used to simulate the wind field of downburst. Considering the maximum wind speed position and the incoming wind vertical to the building facade, the distribution characteristics of wind pressure on the internal and external surfaces of concave, T-shaped and L-shaped low-rise buildings were studied and compared with those of cubical buildings, focusing on the influence of the setting mode of facade openings on the wind pressure distribution. The results show that for the three types of irregular buildings, the change of opening position has little impact on the wind pressure coefficient on external surface, but it has a great impact on the wind pressure coefficient on internal surface. Among them, the opening on the windward side has the most significant impact on the internal surface pressure coefficient distribution, and the ventilation is the main reason for the reduction of internal surface pressure coefficient. When opening on both front and rear sides, the wind pressure coefficient in the center of the windward side near the upper and lower edges of the opening increases and decreases sharply. The wind pressure coefficient difference of the upper and lower edges of the concave building opening is the largest, which is 0.288, and the wind pressure coefficient difference of the upper and lower edges of the T-shaped building opening is the smallest, which is 0.137. There is a small difference in wind pressure coefficients on the transverse midline of the windward side among the five opening modes of the concave and L-type buildings, but there is a great difference among the five opening modes of the T-type buildings. Compared with closed buildings, when opening on one side, the combined wind pressure coefficients of the concave, T-type and L-type building roofs under internal and external wind pressure increase the most, which are 348.6%, 493.6% and 250.7%, respectively.更多还原