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Quadratic analysis of boundary layer above pitched and flat roofs

Publication at Faculty of Mathematics and Physics |
2009

Abstract

Boundary layer over two types of urban roughness in wind-tunnel is investigated. The roughness is composed from rows of street canyons with two shapes of roof- flat and pitched.

Momentum flux and corresponding transport exhibits diverse development, extension and magnitude as well. Ventilation in streets is therefore distinct from each other.

Flat roofs generate rather larger eddies in street canyon, which does not disturb the ventilation significantly. Adversely, geometry of pitched roofs enables to wind to attack on the core of recirculation zone and break it.

Quadrant analysis is 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.