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Original title:
Turbulent Boundary Layer generated Over Two Urban Roughnesses
Authors: Kellnerová, Radka ; Jaňour, Zbyněk
Document type: Papers
Conference/Event: Experimental Fluid Mechanics 2009, Liberec (CZ), 2009-11-25 / 2009-11-27
Year: 2009
Language: eng
Abstract: As a basis for PIV measurement, turbulent characteristics of a flow were investigated by LDA over two different types of urban roughness in wind-tunnel. The roughness consists from long series of street canyons with unit aspect ratio. Different shapes of roof - flat and pitched - provide a different internal boundary layer above canyons. The latter one, generated by pitched roofs, is significantly more turbulent and thus slower then above flat roofs. Momentum flux and corresponding transport exhibits the largest deviation specially at the roof level. Ventilation in the streets is therefore distinct from each other. Quadrant analysis was applied for vertical profiles and cross-sectional areas in canyons in order to detect a domination of sweep or ejection events and to find a linkage to the third moment of velocity for both cases. The overall goal of the project is to find any of coherent structure produced by the roof edge as a low momentum region or an ejection formed by hairpin.
Keywords: flat and pitched roof; quadrant analysis; street canyon; wavelet analysis
Project no.: CEZ:AV0Z20760514 (CEP), OC 113
Funding provider: GA MŠk
Host item entry: Experimental Fluid Mechanics 2009, ISBN 978-80-7372-538-9
Institution: Institute of Thermomechanics AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0178169
Permalink: http://www.nusl.cz/ntk/nusl-40820
The record appears in these collections:
Research > Institutes ASCR > Institute of Thermomechanics
Conference materials > Papers
Authors: Kellnerová, Radka ; Jaňour, Zbyněk
Document type: Papers
Conference/Event: Experimental Fluid Mechanics 2009, Liberec (CZ), 2009-11-25 / 2009-11-27
Year: 2009
Language: eng
Abstract: As a basis for PIV measurement, turbulent characteristics of a flow were investigated by LDA over two different types of urban roughness in wind-tunnel. The roughness consists from long series of street canyons with unit aspect ratio. Different shapes of roof - flat and pitched - provide a different internal boundary layer above canyons. The latter one, generated by pitched roofs, is significantly more turbulent and thus slower then above flat roofs. Momentum flux and corresponding transport exhibits the largest deviation specially at the roof level. Ventilation in the streets is therefore distinct from each other. Quadrant analysis was applied for vertical profiles and cross-sectional areas in canyons in order to detect a domination of sweep or ejection events and to find a linkage to the third moment of velocity for both cases. The overall goal of the project is to find any of coherent structure produced by the roof edge as a low momentum region or an ejection formed by hairpin.
Keywords: flat and pitched roof; quadrant analysis; street canyon; wavelet analysis
Project no.: CEZ:AV0Z20760514 (CEP), OC 113
Funding provider: GA MŠk
Host item entry: Experimental Fluid Mechanics 2009, ISBN 978-80-7372-538-9
Institution: Institute of Thermomechanics AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0178169
Permalink: http://www.nusl.cz/ntk/nusl-40820
The record appears in these collections:
Research > Institutes ASCR > Institute of Thermomechanics
Conference materials > Papers
Record created 2011-07-01, last modified 2024-01-26