The effect of courtyard buildings on the ventilation of street canyons: A wind-tunnel study

0550731 - ÚT 2023 RIV NL eng J - Journal Article
Nosek, Štěpán - Kluková, Zuzana - Jakubcová, Michala - Jaňour, Zbyněk
The effect of courtyard buildings on the ventilation of street canyons: A wind-tunnel study.
Journal of Wind Engineering and Industrial Aerodynamics. Roč. 220, January (2022), č. článku 104885. ISSN 0167-6105. E-ISSN 1872-8197
Institutional support: RVO:61388998
Keywords : urban air pollution * street canyon * courtyards * roof geometry * wind tunnel * coherent structures * TR-PIV * OPD
OECD category: Meteorology and atmospheric sciences
Impact factor: 4.8, year: 2022
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0167610521003585

Using controlled tests in a wind tunnel, we simulated the pollution of four different street canyons formed by four 3D urban array models. The urban models differed by the geometry of roofs (pitched and flat roofs) and buildings (courtyard and solid buildings). We simulated traffic pollution from a ground-level source positioned in the middle of the street canyons. We show that the courtyard buildings significantly improve (by a factor of 1.3) the ventilation of the street canyons only in the cases with pitched roofs. We explain the differences between the ventilation performances of the street canyons by analysing the dynamics of the coherent structures. The buildings at the roof level shed two main vortex structures into the flow. However, the street canyon with pitched roofs and the courtyard buildings shed more stable structures that collide and penetrate deeper downstream near the wind-facing eaves. Near the pedestrian zone, ventilation is driven by advection, manifested as corner vortices at the street ends and flow convergence from the windward to the leeward side in the middle of the street canyons. The corner vortices are more pronounced in the courtyard buildings regardless of roof shape, resulting in higher concentrations than solid buildings.
Permanent Link: https://hdl.handle.net/11104/0332774