【摘要】 采用RNG k-ε湍流模型模拟下击暴流场,在与已有建筑下击暴流场试验数据进行对比验证的基础上,模拟分析了下击暴流对双坡屋面建筑的风压作用;侧重考虑了建筑处于下击暴流径向最大风速位置（r/D₀=1.0）处,风向与坡角变化及有无挑檐对风压分布的影响。分析结果表明:风向与坡角的变化对表面风压有显著影响,坡角变化时,屋面风荷载体型系数最大增幅达到152.2%;随风向角增大,迎风面总体风荷载体型系数呈显著减小趋势,而背风面的负压绝对值则有较大提高,其系数变化幅度达到120.7%;因风向变化,侧风面风荷载体型系数出现261.4%的增幅;有无挑檐对建筑表面风压也产生影响,但主要表现在迎风面近挑檐区域的风压发生较大改变。更多还原

【Abstract】 The downburst field is simulated by RNG k-ε turbulence model in this paper. On basis of comparison between simulation and test data of the existing building, the wind pressure effect of downburst on gable roofs building is simulated and analyzed, focused on the influence of roof slope and presence or absence of cornice on wind load distribution in the vicinity of radial location（r/D₀=1.0）. The results show that the change of wind direction and slope angle has significant influence on surface wind pressure distribution. For instance the wind load shape coefficient of roof facade increased up to 152.2%, which is affected by the slope angle. As the wind direction angle increases, the total wind load shape coefficient on windward facade decreases significantly, while the negative pressure absolute value on leeward facade greatly increases, with the coefficient of variation reaching to 120.7%. Due to the change of wind direction, wind load shape coefficient will appear increase amplitude of 261.4% in proximity to crosswind facade. Surface wind pressure also has been impacted by the cornice, but the wind pressure mainly changed in the windward of proximity to cornices.更多还原