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Article: Pollutant dispersion in idealized city models with different urban morphologies

TitlePollutant dispersion in idealized city models with different urban morphologies
Authors
KeywordsCFD simulation
City form
Pollutant dispersion
Urban morphology
Issue Date2009
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/atmosenv
Citation
Atmospheric Environment, 2009, v. 43 n. 38, p. 6011-6025 How to Cite?
AbstractThe mechanism of pollutant dispersion in idealized city models is investigated numerically by the introduction of a uniformly distributed pollutant source at street pedestrian level. We first study three short city forms with a single main street or two crossing streets, characterized by street length/street height ratios of L/H = 6 or 7 and a street height/street width ratio of H/W = 1, including a sharp-edged round city model, a smooth-edged round city model, and a sharp-edged square city model. For short city models with a single street and a parallel approaching wind, pollutant dilution mainly depends on the horizontal flow rate which decreases along the street. This decreasing rate is smallest for the smooth-edged round city model, which results in the lowest street concentrations. For city models with two crossing streets and the approaching wind parallel to the main street, the differences in overall city form result in different dispersion processes. For a sharp-edged round city model with two crossing streets, an approaching wind slightly non-parallel to the main street generates a lower pollutant concentration in the entire street volume. We also studied a sharp-edged round city model with one narrow street (L/H = 6; H/W = 6.7), finding that the uniformly distributed pollutants are transported from two street entries to the city centre, and are then removed out across the street roof. In contrast to the short city models we studied a single-street sharp-edged long rectangular city model (L/H = 21.7; H/W = 1) in which the horizontal flow rate remained nearly constant in a region far from the two entries. Within this region the turbulence across the street roof contributed more to the pollutant removal than vertical mean flows. © 2009 Elsevier Ltd. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/124820
ISSN
2015 Impact Factor: 3.459
2015 SCImago Journal Rankings: 1.999
ISI Accession Number ID
Funding AgencyGrant Number
Research Grants Council of the Hong Kong SAR GovernmentHKU 7145/07E
Funding Information:

The work described in this paper was supported by a grant entitled CityVent - A Theory of Ventilation of a Dense and High-Rise City by Wind and Buoyancy Forces from the Research Grants Council of the Hong Kong SAR Government (Project No. HKU 7145/07E). The valuable comments by Prof, James Axley, School of Architecture; School of Forestry & Environmental Studies, Yale University, USA, on the manuscript are also gratefully acknowledged.

References

 

DC FieldValueLanguage
dc.contributor.authorHang, Jen_HK
dc.contributor.authorSandberg, Men_HK
dc.contributor.authorLi, Yen_HK
dc.contributor.authorClaesson, Len_HK
dc.date.accessioned2010-10-31T10:56:03Z-
dc.date.available2010-10-31T10:56:03Z-
dc.date.issued2009en_HK
dc.identifier.citationAtmospheric Environment, 2009, v. 43 n. 38, p. 6011-6025en_HK
dc.identifier.issn1352-2310en_HK
dc.identifier.urihttp://hdl.handle.net/10722/124820-
dc.description.abstractThe mechanism of pollutant dispersion in idealized city models is investigated numerically by the introduction of a uniformly distributed pollutant source at street pedestrian level. We first study three short city forms with a single main street or two crossing streets, characterized by street length/street height ratios of L/H = 6 or 7 and a street height/street width ratio of H/W = 1, including a sharp-edged round city model, a smooth-edged round city model, and a sharp-edged square city model. For short city models with a single street and a parallel approaching wind, pollutant dilution mainly depends on the horizontal flow rate which decreases along the street. This decreasing rate is smallest for the smooth-edged round city model, which results in the lowest street concentrations. For city models with two crossing streets and the approaching wind parallel to the main street, the differences in overall city form result in different dispersion processes. For a sharp-edged round city model with two crossing streets, an approaching wind slightly non-parallel to the main street generates a lower pollutant concentration in the entire street volume. We also studied a sharp-edged round city model with one narrow street (L/H = 6; H/W = 6.7), finding that the uniformly distributed pollutants are transported from two street entries to the city centre, and are then removed out across the street roof. In contrast to the short city models we studied a single-street sharp-edged long rectangular city model (L/H = 21.7; H/W = 1) in which the horizontal flow rate remained nearly constant in a region far from the two entries. Within this region the turbulence across the street roof contributed more to the pollutant removal than vertical mean flows. © 2009 Elsevier Ltd. All rights reserved.en_HK
dc.languageengen_HK
dc.publisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/atmosenven_HK
dc.relation.ispartofAtmospheric Environmenten_HK
dc.subjectCFD simulationen_HK
dc.subjectCity formen_HK
dc.subjectPollutant dispersionen_HK
dc.subjectUrban morphologyen_HK
dc.titlePollutant dispersion in idealized city models with different urban morphologiesen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1352-2310&volume=43&issue=38&spage=6011&epage=6025&date=2009&atitle=Pollutant+dispersion+in+idealized+city+models+with+different+urban+morphologiesen_HK
dc.identifier.emailLi, Y:liyg@hkucc.hku.hken_HK
dc.identifier.authorityLi, Y=rp00151en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.atmosenv.2009.08.029en_HK
dc.identifier.scopuseid_2-s2.0-71049178306en_HK
dc.identifier.hkuros180416en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-71049178306&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume43en_HK
dc.identifier.issue38en_HK
dc.identifier.spage6011en_HK
dc.identifier.epage6025en_HK
dc.identifier.isiWOS:000272276000004-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridHang, J=35240092500en_HK
dc.identifier.scopusauthoridSandberg, M=35585315900en_HK
dc.identifier.scopusauthoridLi, Y=7502094052en_HK
dc.identifier.scopusauthoridClaesson, L=8934695800en_HK
dc.identifier.citeulike5731788-

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