Validation of a two-dimensional pollutant dispersion model in an isolated street canyon

• Published in: Atmospheric environment (1994) Vol. 36; no. 5; pp. 861 - 872
• Main Authors: Chan, T.L., Dong, G., Leung, C.W., Cheung, C.S., Hung, W.T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-02-2002; Elsevier Science
• Subjects: Applied sciences; Atmospheric pollution; Convection, turbulence, diffusion. Boundary layer structure and dynamics; Earth, ocean, space; Exact sciences and technology; External geophysics; k– ε turbulence models; Meteorology; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Street canyon; Two-dimensional pollutant dispersion model; Vehicle emissions; Wind tunnel data; Street canyon; k– ε turbulence models; Wind tunnel data; Vehicle emissions; Two-dimensional pollutant dispersion model; Performance evaluation; Air quality; Two dimensional model; Motor vehicle; Urban area; Wind tunnel; Urban road traffic; Complex terrain; Pollution source; Air pollution; Numerical simulation; Atmospheric dispersion; Moving source
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/S1352-2310(01)00490-3

A two-dimensional numerical model based on Reynolds-averaged Navier–Stokes equations coupled with a series of standard, Renormalization Group (RNG) and realizable
k–
ε turbulence models was developed to simulate the fluid-flow development and pollutant dispersion within an isolated street canyon using the FLUENT code. In the present study, the validation of the numerical model was evaluated using an extensive experimental database obtained from the atmospheric boundary layer wind tunnel at the Meteorological Institute of Hamburg University, Germany (J. Wind Eng. Ind. Aerodyn. 62 (1996) 37)
. Among the studied turbulence models, the RNG
k–
ε turbulence model was found to be the most optimum turbulence model coupled with the two-dimensional street canyon model developed in the present study. Both the calculated and measured dimensionless pollutant concentrations have been shown to be less dependent on the variation of wind speed and source strength conditions for the studied street canyon aspect ratio of the
B/
H=1 case. However, the street canyon configuration has significant influence on the pollutant dispersion. The wider street and lower height of the buildings are favorable to pollutant dilution within the street canyon. The fluid-flow development has demonstrated that the rotative vortex or vortices generated within the urban street canyon can transport the pollutants from a line source to the wall surfaces of the buildings.