| NUMERICAL STUDIES ON AIRFLOW AND POLLUTANT DISPERSION IN URBAN STREET CANYONS FORMED BY SLANTED ROOF BUILDINGS |
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| 作者姓名： | HUANG Yuan-dong JIN Ming-xia SUN Ya-nan |
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| 作者单位： | HUANG Yuan-dong，JIN Ming-xia，SUN Ya-nan School of Civil and Environmental Engineering，University of Shanghai for Science and Technology，Shanghai 200093，China |
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| 摘 要： | Based on the CFD technique, fifteen cases were evaluated for the airflows and pollutant dispersions inside urban street canyons formed by slanted roof buildings. The simulated wind fields and concentration contours show that W/H, W/h and h/H (where W is the street width, and H and h are the heights of buildings at the leeward and windward sides of the street, respectively) are the crucial factors in determining the vortex structure and pollutant distribution within a canyon. It is concluded that (1) in a symmetrical canyon, at W/H =0.5 two vortices (an upper clockwise vortex between the slanted roofs and a lower counter-clockwise one) are developed and pollutants accumulate on the windward side of the street, whereas at W/H=2.0 only one clockwise vortex is generated and thus pollution piles up on the leeward side, (2) in a step-up canyon with W/H =0.5 to 2.0 (at h/H =1.5 to 2.0)and a step-down canyon with W/h=1.0 (at h/H =0.5 to 0.667), the pollution level close to the lower building is higher than that close to the taller building since a clockwise vortex is generated in the step-up canyon and a counter-clockwise one in the step-down canyon, (3) in a narrow step-down canyon with W/h=0.5 (at h/H =0.667) very poor ventilation properties is detected, and inside a wider step-down canyon with W/h=2.0 the vortex structure and consequently pollutant distribution varies greatly with h/H.
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| 关 键 词： | 城市街道峡谷 斜屋顶建筑物 气流 污染物扩散 数值模拟 |
| 收稿时间： | 2005-12-15 |
| 修稿时间： | 2006-09-05 |
NUMERICAL STUDIES ON AIRFLOW AND POLLUTANT DISPERSION IN URBAN STREET CANYONS FORMED BY SLANTED ROOF BUILDINGS |
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| HUANG Yuan-dong JIN Ming-xia SUN Ya-nan.NUMERICAL STUDIES ON AIRFLOW AND POLLUTANT DISPERSION IN URBAN STREET CANYONS FORMED BY SLANTED ROOF BUILDINGS[J].Journal of Hydrodynamics,2007,19(1):100-106. |
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| Authors: | HUANG Yuan-dong JIN Ming-xia SUN Ya-nan |
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| Affiliation: | 1. Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR;2. Ventilation and Air Quality Centre for Built Environment, University of Gävle, SE-801 76 Gävle, Sweden;1. College of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, China;2. College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China |
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| Abstract: | Based on the CFD technique, fifteen cases were evaluated for the airflows and pollutant dispersions inside urban street canyons formed by slanted roof buildings. The simulated wind fields and concentration contours show that W/H, W/h and h/H (where W is the street width, and H and h are the heights of buildings at the leeward and windward sides of the street, respectively) are the crucial factors in determining the vortex structure and pollutant distribution within a canyon. It is concluded that (1) in a symmetrical canyon, at W/H =0.5 two vortices (an upper clockwise vortex between the slanted roofs and a lower counter-clockwise one) are developed and pollutants accumulate on the windward side of the street, whereas at W/H=2.0 only one clockwise vortex is generated and thus pollution piles up on the leeward side, (2) in a step-up canyon with W/H =0.5 to 2.0 (at h/H =1.5 to 2.0)and a step-down canyon with W/h=1.0 (at h/H =0.5 to 0.667), the pollution level close to the lower building is higher than that close to the taller building since a clockwise vortex is generated in the step-up canyon and a counter-clockwise one in the step-down canyon, (3) in a narrow step-down canyon with W/h=0.5 (at h/H =0.667) very poor ventilation properties is detected, and inside a wider step-down canyon with W/h=2.0 the vortex structure and consequently pollutant distribution varies greatly with h/H. |
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| Keywords: | numerical simulation wind flow pollutant dispersion street canyons slanted roof buildings |
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