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Article: Impact of building facades and ground heating on wind flow and pollutant transport in street canyons

TitleImpact of building facades and ground heating on wind flow and pollutant transport in street canyons
Authors
KeywordsCFD
Isolated roughness flow
Pollutant transport
Skimming flow
Wake interference flow
Issue Date2007
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/atmosenv
Citation
Atmospheric Environment, 2007, v. 41 n. 39, p. 9030-9049 How to Cite?
AbstractThis paper investigates the impacts of building facades and ground heating on the wind flow and pollutant transport in street canyons using the computational fluid dynamic (CFD) technique. Street canyons of H/W (H representing the building height and W the street width) varied from 0.1 to 2, which covered the basic flow regimes of skimming flow (H/W=1 or 2), wake interference flow (H/W=0.5), and isolated roughness flow (H/W=0.1), were examined in a series of sensitivity tests. Heating that occurred on different surfaces, including ground surface and building façades, posed considerable effects on the street canyon wind flow and pollutant transport compared with those under isothermal conditions. The CFD results showed that the mechanically induced wind flow and pollutant transport were complicated by the buoyancy under temperature stratification. Individual street canyons of different H/W and surface-heating scenarios exhibited their unique wind flow structure and pollutant transport behaviors. Two counter-rotating vortices were calculated in the street canyons of H/W=1, in which the zone of higher pollutant concentration under isothermal conditions was switched from the leeward side to the windward side. In the street canyon of H/W=2, the recirculating wind pattern was perturbed by surface heating that led to the development of either one primary vortex or three closely coupled vortices. Because of the complicated wind structure, the zones of higher pollutant concentration located either on the leeward or windward ground level were subjected to the surface-heating scenarios. Only two vortices were developed inside the street canyon of H/W=0.5. The large primary vortex, centered inside the street canyon, extended above the roof level of the street canyon. Meanwhile, a small secondary vortex was found at the ground-level windward corner whose size results as a function of surface-heating configurations. Finally, in the street canyon of H/W=0.1, an isolated clockwise-rotating vortex was developed beside the leeward building while the wind in the windward side blew in the prevailing wind direction. As a result, air pollutant emitted at the street centerline was unlikely to be carried into the leeward vortex. Instead, it was dispersed rapidly on the windward side before being removed from the street canyon. © 2007 Elsevier Ltd. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/75911
ISSN
2015 Impact Factor: 3.459
2015 SCImago Journal Rankings: 1.999
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorXie, Xen_HK
dc.contributor.authorLiu, CHen_HK
dc.contributor.authorLeung, DYCen_HK
dc.date.accessioned2010-09-06T07:15:46Z-
dc.date.available2010-09-06T07:15:46Z-
dc.date.issued2007en_HK
dc.identifier.citationAtmospheric Environment, 2007, v. 41 n. 39, p. 9030-9049en_HK
dc.identifier.issn1352-2310en_HK
dc.identifier.urihttp://hdl.handle.net/10722/75911-
dc.description.abstractThis paper investigates the impacts of building facades and ground heating on the wind flow and pollutant transport in street canyons using the computational fluid dynamic (CFD) technique. Street canyons of H/W (H representing the building height and W the street width) varied from 0.1 to 2, which covered the basic flow regimes of skimming flow (H/W=1 or 2), wake interference flow (H/W=0.5), and isolated roughness flow (H/W=0.1), were examined in a series of sensitivity tests. Heating that occurred on different surfaces, including ground surface and building façades, posed considerable effects on the street canyon wind flow and pollutant transport compared with those under isothermal conditions. The CFD results showed that the mechanically induced wind flow and pollutant transport were complicated by the buoyancy under temperature stratification. Individual street canyons of different H/W and surface-heating scenarios exhibited their unique wind flow structure and pollutant transport behaviors. Two counter-rotating vortices were calculated in the street canyons of H/W=1, in which the zone of higher pollutant concentration under isothermal conditions was switched from the leeward side to the windward side. In the street canyon of H/W=2, the recirculating wind pattern was perturbed by surface heating that led to the development of either one primary vortex or three closely coupled vortices. Because of the complicated wind structure, the zones of higher pollutant concentration located either on the leeward or windward ground level were subjected to the surface-heating scenarios. Only two vortices were developed inside the street canyon of H/W=0.5. The large primary vortex, centered inside the street canyon, extended above the roof level of the street canyon. Meanwhile, a small secondary vortex was found at the ground-level windward corner whose size results as a function of surface-heating configurations. Finally, in the street canyon of H/W=0.1, an isolated clockwise-rotating vortex was developed beside the leeward building while the wind in the windward side blew in the prevailing wind direction. As a result, air pollutant emitted at the street centerline was unlikely to be carried into the leeward vortex. Instead, it was dispersed rapidly on the windward side before being removed from the street canyon. © 2007 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.subjectCFDen_HK
dc.subjectIsolated roughness flowen_HK
dc.subjectPollutant transporten_HK
dc.subjectSkimming flowen_HK
dc.subjectWake interference flowen_HK
dc.titleImpact of building facades and ground heating on wind flow and pollutant transport in street canyonsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1352-2310&volume=41&spage=9030&epage=9049&date=2007&atitle=Impact+of+building+facades+and+ground+heating+on+wind+flow+and+pollutant+transport+in+street+canyonsen_HK
dc.identifier.emailLiu, CH:chliu@hkucc.hku.hken_HK
dc.identifier.emailLeung, DYC:ycleung@hku.hken_HK
dc.identifier.authorityLiu, CH=rp00152en_HK
dc.identifier.authorityLeung, DYC=rp00149en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.atmosenv.2007.08.027en_HK
dc.identifier.scopuseid_2-s2.0-36849038026en_HK
dc.identifier.hkuros144569en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-36849038026&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume41en_HK
dc.identifier.issue39en_HK
dc.identifier.spage9030en_HK
dc.identifier.epage9049en_HK
dc.identifier.isiWOS:000252260400016-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridXie, X=55186474400en_HK
dc.identifier.scopusauthoridLiu, CH=36065161300en_HK
dc.identifier.scopusauthoridLeung, DYC=7203002484en_HK

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