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Article: Wind conditions and ventilation in high-rise long street models

TitleWind conditions and ventilation in high-rise long street models
Authors
KeywordsAir change rate (ACH)
Flow rate
High-rise long street
Numerical simulation
Turbulent exchange
Wind tunnel
Issue Date2010
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/buildenv
Citation
Building And Environment, 2010, v. 45 n. 6, p. 1353-1365 How to Cite?
AbstractWe regarded high-rise cities as obstacles and channels to wind. We first studied wind conditions and ventilations in idealized high-rise long street models experimentally and numerically with a constant street width (W = 30 mm), variable street heights (H = 2 W, 2.5W, 3W, 4W), variable street lengths (L = 47.4W, 79W, 333W, 667W) and a parallel approaching wind. The flow rates penetrating into windward entries are a little larger than the reference flow rate in the far upstream free flow through the same area with windward entries in all models. The stream-wise velocity decreases along the street as some air leaves upwardly across street roofs. Near the leeward entry, there is a downward flow which brings some air into the street and results in an accelerating process. In the neighborhood scale long streets (L = 47.4W and 79W), wind in taller streets is stronger and the ventilation is better than a lower one. For the city scale long streets (L = 333W and 667W), a constant flow region exists where the vertical velocity is zero and the stream-wise velocity remains constant. In such regions, turbulent fluctuations across the street roof are more important to air exchange than vertical mean flows. In a taller street, the process to establish the constant flow conditions is longer and the normalized balanced horizontal flow rate is smaller than those in a lower street. In the city scale long streets, the turbulence exchange rate can be 5-10 times greater than the mean flow rate. Crown Copyright © 2009.
Persistent Identifierhttp://hdl.handle.net/10722/124873
ISSN
2015 Impact Factor: 3.394
2015 SCImago Journal Rankings: 2.121
ISI Accession Number ID
Funding AgencyGrant Number
Research Grants Council of the Hong Kong SAR GovernmentHKU 7145/07E
Funding Information:

This work was supported by a grant from the Research Grants Council of the Hong Kong SAR Government (Project No. HKU 7145/07E). The help by Mr. R Peltary with building wind-tunnels models, Mr. H Lundstom with the measuring equipment 1, all from the University of Gavle, is gratefully acknowledged. We also thank two anonymous reviewers for their constructive comments which have improved this paper.

References

 

DC FieldValueLanguage
dc.contributor.authorHang, Jen_HK
dc.contributor.authorLi, Yen_HK
dc.contributor.authorSandberg, Men_HK
dc.contributor.authorClaesson, Len_HK
dc.date.accessioned2010-10-31T10:58:53Z-
dc.date.available2010-10-31T10:58:53Z-
dc.date.issued2010en_HK
dc.identifier.citationBuilding And Environment, 2010, v. 45 n. 6, p. 1353-1365en_HK
dc.identifier.issn0360-1323en_HK
dc.identifier.urihttp://hdl.handle.net/10722/124873-
dc.description.abstractWe regarded high-rise cities as obstacles and channels to wind. We first studied wind conditions and ventilations in idealized high-rise long street models experimentally and numerically with a constant street width (W = 30 mm), variable street heights (H = 2 W, 2.5W, 3W, 4W), variable street lengths (L = 47.4W, 79W, 333W, 667W) and a parallel approaching wind. The flow rates penetrating into windward entries are a little larger than the reference flow rate in the far upstream free flow through the same area with windward entries in all models. The stream-wise velocity decreases along the street as some air leaves upwardly across street roofs. Near the leeward entry, there is a downward flow which brings some air into the street and results in an accelerating process. In the neighborhood scale long streets (L = 47.4W and 79W), wind in taller streets is stronger and the ventilation is better than a lower one. For the city scale long streets (L = 333W and 667W), a constant flow region exists where the vertical velocity is zero and the stream-wise velocity remains constant. In such regions, turbulent fluctuations across the street roof are more important to air exchange than vertical mean flows. In a taller street, the process to establish the constant flow conditions is longer and the normalized balanced horizontal flow rate is smaller than those in a lower street. In the city scale long streets, the turbulence exchange rate can be 5-10 times greater than the mean flow rate. Crown Copyright © 2009.en_HK
dc.languageengen_HK
dc.publisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/buildenven_HK
dc.relation.ispartofBuilding and Environmenten_HK
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Building and Environment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Building and Environment, 2010, v. 45 n. 6, p. 1353-1365. DOI: 10.1016/j.buildenv.2009.11.019-
dc.subjectAir change rate (ACH)en_HK
dc.subjectFlow rateen_HK
dc.subjectHigh-rise long streeten_HK
dc.subjectNumerical simulationen_HK
dc.subjectTurbulent exchangeen_HK
dc.subjectWind tunnelen_HK
dc.titleWind conditions and ventilation in high-rise long street modelsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0360-1323&volume=45&issue=6&spage=1353&epage=1365&date=2010&atitle=Wind+conditions+and+ventilation+in+high-rise+long+street+modelsen_HK
dc.identifier.emailLi, Y:liyg@hkucc.hku.hken_HK
dc.identifier.authorityLi, Y=rp00151en_HK
dc.description.naturepostprint-
dc.identifier.doi10.1016/j.buildenv.2009.11.019en_HK
dc.identifier.scopuseid_2-s2.0-75949084439en_HK
dc.identifier.hkuros180419en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-75949084439&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume45en_HK
dc.identifier.issue6en_HK
dc.identifier.spage1353en_HK
dc.identifier.epage1365en_HK
dc.identifier.isiWOS:000275515400001-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridHang, J=35240092500en_HK
dc.identifier.scopusauthoridLi, Y=7502094052en_HK
dc.identifier.scopusauthoridSandberg, M=35585315900en_HK
dc.identifier.scopusauthoridClaesson, L=8934695800en_HK
dc.identifier.citeulike6483231-

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