Turbulent Boundary Layer generated Over Two Urban Roughnesses

0333098 - ÚT 2010 RIV CZ eng C - Konferenční příspěvek (zahraniční konf.)
Kellnerová, Radka - Jaňour, Zbyněk
Turbulent Boundary Layer generated Over Two Urban Roughnesses.
Experimental Fluid Mechanics 2009. Liberec: Technical University of Liberec, 2009 - (Vít, T.; Dančová, P.; Dvořák, V.), s. 109-118. ISBN 978-80-7372-538-9.
[Experimental Fluid Mechanics 2009. Liberec (CZ), 25.11.2009-27.11.2009]
Grant CEP: GA MŠMT OC 113
Výzkumný záměr: CEZ:AV0Z20760514
Klíčová slova: street canyon * flat and pitched roof * quadrant analysis * wavelet analysis
Kód oboru RIV: DG - Vědy o atmosféře, meteorologie

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.
Trvalý link: http://hdl.handle.net/11104/0178169