Title: Large-eddy simulation of flows over two-dimensional idealised street canyons with height variation
Authors: Colman C.C. Wong; Chun-Ho Liu
Addresses: 7/F Haking Wong Building, Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong ' 7/F Haking Wong Building, Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
Abstract: A series of large-eddy simulation (LES) models consisting of two-dimensional (2D) idealised street canyons with building height variability (BHV) are examined. Building blocks with two different heights are placed alternately in the computational domains, constructing repeated street canyons of building-height-to-street-width (aspect) ratio (AR) = 1, 0.5, 0.25 and 0.125 together with BHV = 0.2, 0.4 and 0.6. LES results show that the air exchange rate (ACH) increases with increasing aerodynamic resistance. Apart from AR, BHV is another factor affecting the aerodynamic resistance and thus the ACH. The (vertical) dispersion coefficient σz of plume transport is also closely related to the aerodynamic resistance, suggesting that introducing BHV in urban areas could help improve the air quality.
Keywords: air pollution; computational fluid dynamics; CFD; large-eddy simulation; LES; scalar dispersion; street canyons; height variation; building heights; air exchange rate; ACH; plume transport; aerodynamic resistance; urban areas; air quality.
International Journal of Environment and Pollution, 2014 Vol.54 No.2/3/4, pp.147 - 155
Received: 08 May 2021
Accepted: 12 May 2021
Published online: 13 Oct 2014 *