摘要
基于标准的kε双方程湍流模型,数值模拟了2种峡谷宽高比和4种建筑物宽高比下的开阔地域街道峡谷内部气流场.模拟结果表明,峡谷上部生成一顺时针大旋涡,并在此大旋涡的驱动下,峡谷内部形成一个逆时针旋涡;建筑物宽高比(W/H)对峡谷内部气流场具有显著影响,在W/H较小的情况下(如W/H=1/5),峡谷上部顺时针旋涡向峡谷内扩展而挤压峡谷内的逆时针旋涡,在峡谷宽高比(B/H)一定的前提下,上部顺时针旋涡向峡谷内部扩展的程度随W/H的减小而增大,而在W/H一定的条件下,上部顺时针旋涡向峡谷内部扩展的程度随B/H的加大而增强.从上述峡谷内部流场的特征中可推断出,在建筑物高度一定的条件下,缩小建筑物宽度和加大峡谷宽度会增强峡谷内外空气的交换,从而有利于峡谷内空气品质的改善.
Based on k-ε turbulence model, the wind fields within isolated street canyons under two different canyon width to height ratios and four different building width to height ratios are calculated. The numerical results show that: (1) the incident gas flow is separated at the front upper edge of the upstream building and generates a clockwise rotating vortex in the wake area above the street canyon, which drives a counter-clockwise rotating vortex in the street canyon; (2) the building width to height ratio (W/H) has a great impact on the gas flow field. Under small value of W/H (such as W/H = 1/5), the clockwise rotating vortex above the canyon extends toward the street canyon and compresses the counter-clockwise rotating vortex in the street canyon. The development of clockwise rotating vortex toward the street canyon increases as W/H is decreased from 1/5 to 3/5 under a given value of canyon width to height ratio (B/H), and increases as B/H is increased for a given value of W/H. Obviously, for a given building height, decreasing the building width and increasing the street width are beneficial for exchange of air in and above the street canyon.
出处
《上海理工大学学报》
EI
CAS
北大核心
2005年第3期203-206,共4页
Journal of University of Shanghai For Science and Technology
基金
国家自然科学基金资助项目(70371011)
