Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5751862 | Science of The Total Environment | 2017 | 18 Pages |
Abstract
As a novelty, the two-main-vortex pattern start appearing in full-scale street canyons as H/W changes from 4 to 5, however previous studies using wind-tunnel-scale models (HÂ =Â 6cm) reported two to five vortexes as H/WÂ =Â 2-5. This finding is validated by both smoke visualization in scale-model outdoor field experiments (HÂ =Â 1.2m, WÂ =Â 0.6m) and CFD simulations of Reynolds number independence. Cases with two main vortexes (H/WÂ =Â 5-6) experience much larger daily pollutant exposure (~Â 103-104Â mg/m3/day) than those with single main vortex as H/WÂ =Â 1-4 (~Â 101-102Â mg/m3/day). Moreover leeward-side pollutant exposures are much larger than windward-side as H/WÂ =Â 1-4 while oppositely as H/WÂ =Â 5-6. Assuming a general population density, the total iF is 485-803Â ppm as H/WÂ =Â 1, 2020-12051Â ppm as H/WÂ =Â 2-4, and 51112-794026Â ppm as H/WÂ =Â 5-6. With a single elevated pollutant source, cases with viaducts experience significantly smaller pollutant exposures than cases without viaducts. Road barriers slightly increase pollutant exposure in near-road buildings with H/WÂ =Â 1 while reduce a little as H/WÂ =Â 3 and 5. Two-source cases can experience 2.60-5.52 times pollutant exposure as great as single-source cases.
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Authors
Lejian He, Jian Hang, Xuemei Wang, Borong Lin, Xiaohui Li, Guangdong Lan,