带斜顶建筑物的城市街道峡谷内部气流场数值研究

基于S.R afa ilid is和M.Schatzm ann在风洞中所采用的城市街道峡谷物理模型,数值模拟了6种带有斜顶建筑物的城市街道峡谷内部气流场。模拟结果表明:①建筑物斜顶显著影响峡谷内部的气流场,由于气流绕过斜顶时产生剧烈分离,使得处于背风面的斜顶与处于迎风面的斜顶相比,前者对峡谷内部的气流漩涡结构影响更大;②斜顶建筑物高度与峡谷宽度的比是决定峡谷内部漩涡结构的重要因素,其比值愈大愈易于在峡谷内部生成两个旋转方向相反的漩涡(其中峡谷上部为顺时针漩涡,而下部为逆时针漩涡)。

Numerical simulation of the wind field in urban street canyons with slant building roofs

Based on the physical models for urban street canyons applied by S.Rafailidis and M.Schatzmann in wind tunnel experiments,the wind fields in urban street canyons with slant building roofs are numerically simulated.The numerical results show that the slant roof has a great influence on the wind field in the urban street canyons.Due to the massive separation caused by the wind flow past a slant roof,the leeward building causes greater influence on the vortex structures in urban canyons than the windward building does.The ratio of height of the building with slant roofs to the canyon width(h/b) is a crucial factor in determining the vortex structures in canyons.At greater h/b,such as h/b>1,two vortices are developed,an upper clockwise one driven by ambient airflow and a lower one driven in the opposite direction by the circulation above.