Flow and Pollutant Dispersion in Street Canyons using FLUENT and ADMS-Urban
- 1.1k Downloads
This paper is devoted to the study of flow within a small building arrangement and pollutant dispersion in street canyons starting from the simplest case of dispersion from a simple traffic source. Flow results from the commercial computational fluid dynamics (CFD) code FLUENT are validated against wind tunnel data (CEDVAL). Dispersion results from FLUENT are analysed using the well-validated atmos pheric dispersion model ADMS-Urban. The k − ε turbulence model and the advection-diffusion (AD) method are used for the CFD simulations. Sensitivity of dispersion results to wind direction within street canyons of aspect ratio equal to 1 is investigated. The analysis shows that the CFD model well reproduces the wind tunnel flow measurements and compares adequately with ADMS-Urban dispersion predictions for a simple traffic source by using a slightly modified k − ε model. It is found that a Schmidt number of 0.4 is the most appropriate number for the simulation of a simple traffic source and in street canyons except for the case when the wind direction is perpendicular to the street canyon axis. For this last case a Schmidt number equal to 0.04 gives the best agreement with ADMS-Urban. Overall the modified k − ε turbulence model may be accurate for the simulation of pollutant dispersion in street canyons provided that an appropriate choice for coefficients in the turbulence model and the Schmidt number in the diffusion model are made.
KeywordsStreet canyons Dispersion Modelling FLUENT ADMS-Urban
The authors kindly acknowledge CERC for making available ADMS-Urban for this study. We also thank Dr. D. Carruthers for useful discussions.
- 1.Barth, T. J., & Jespersen, D. (1989). The design and application of upwind schemes on unstructured meshes. Technical Report AIAA-89-0366. AIAA 27th Aerospace Sciences Meeting, Reno, Nevada.Google Scholar
- 2.Berkowicz, R., Ketzel, M., Vachon, G., Louka, P., Rosant, J.-M., Mestayer, P. G., et al. (2002). Examination of traffic pollution distribution in a street canyon using the Nantes ′99 experimental data and comparison with model results. Water, Air & Soil Pollution. Focus, 2(5), 311–324.CrossRefGoogle Scholar
- 3.Carruthers, D., Blair, J., & Johnson, K. (2003). Comparison of ADMS-Urban, NETCEN and ERG air quality predictions for london. CERC report (FM489/R7/03). Available from Cambridge Environmental Research Consultants, 3 Kings Parade,Cambridge, CB2 1SJ, UK.Google Scholar
- 4.Carruthers, D. J., Edmunds, H. A., Lester, A. E., McHugh, C. A., & Singles, R. J. (2000). Use and validation of adms-urban in contrasting urban and industrial locations. International Journal of Environment and Pollution, 14, 1–6.Google Scholar
- 6.CEDVAL dataset (2002). Category B1-4 (flow across an intersection). http://www.mi.uni-hamburg.de/cedval.
- 7.DeCroix, D., & Brown, M. (2002). Report on CFD model evaluation using URBAN 2000 field experiment data. Technical report. IOP 10, LA-UR-02-4755. Available from Los Alamos National Laboratory.Google Scholar
- 8.Di Sabatino, S., Buccolieri, R., Pulvirenti, B., & Britter, R. E. (2005). Flow and pollutant dispersion modelling in street canyons using Fluent and ADMS-Urban. Proc. 5th International Conference on Urban Air Quality. Valencia.Google Scholar
- 9.Fluent (2005). 6.2 User’s Manual. Retrieved at http://www.fluent.com.
- 11.Hanna, S. R., Chang, J., Britter, R. E., & Neophytou, M. (2003). Overview of model evaluation history and procedures in the atmospheric air quality area. QNET-CFD Network Newsletter, 2, 26–28.Google Scholar
- 12.Hanna, S. R., Egan, B. A., Purdum, J., & Wagler, J. (2001). Evaluation of the ADMS, AERMOD and ISC3 models with the Optex, Duke Forest, Kincaid, Indianapolis and Lovett field data sets. International Journal of Environment and Pollution, 16, 1–6.Google Scholar
- 13.Hertel, O., & Berkowicz, R. (1989). Operational street pollution model (OSPM). Evaluation of model on data from st. olavs street in oslo. DMU Luft, A-135.Google Scholar
- 14.Launder, B. E. (1989). Second-moment closure: Present... and future? International Journal of Heat Fluid Flow, 10(4), 2829–300.Google Scholar
- 22.Roache, P. J. (1998). Verification and validation in computational science and engineering. Albuquerque, New Mexico, USA: Hermosa Publishers.Google Scholar
- 23.Schlichting, H. (1979). Boundary-layer theory. New York: McGraw-Hill.Google Scholar