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Heat transfer from the stagnation region of a heated cylinder at ReD = 140000 affected by free-stream turbulence

Wissink, J.; Rodi, W. 1
1 Institut für Hydromechanik (IFH), Karlsruher Institut für Technologie (KIT)

Abstract:

Wind-tunnel studies of dispersion processes of traffic exhaust in urban street canyons with tree planting were performed and tracer gas concentrations using electron capture detection (ECD) and flow fields using laser Doppler velocimetry (LDV) were measured. It was found that tree planting reduce the air exchange between street canyons and the ambience. In comparison to treeless street canyons, higher overall pollutant concentrations and lower flow velocities were measured. In particular, for perpendicular approaching wind, markedly higher concentrations at the leeward canyon wall and slightly lower concentrations at the windward canyon wall were observed. Furthermore, a new approach is suggested to model porous vegetative structures such as tree crowns for small-scale wind-tunnel applications. The approach is based on creating different model tree crown porosities by incorporating a certain amount of wadding material into a specified volume. A significant influence of the crown porosity on pollutant concentrations was found for high degrees of porosity, however, when it falls below a certain threshold, no further changes in pollutant concentrations were observed.


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Originalveröffentlichung
DOI: 10.1016/j.ijheatmasstransfer.2011.02.008
Scopus
Zitationen: 10
Web of Science
Zitationen: 10
Dimensions
Zitationen: 10
Zugehörige Institution(en) am KIT Institut für Hydromechanik (IFH)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2011
Sprache Englisch
Identifikator ISSN: 0017-9310
KITopen-ID: 1000032018
Erschienen in International Journal of Heat and Mass Transfer
Verlag Elsevier
Band 54
Heft 11-12
Seiten 2535-2541
Nachgewiesen in Dimensions
Scopus
Web of Science
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