Comparison of RANS, URANS and LES in the Prediction of Airflow and Pollutant Dispersion

The performance of three different numerical techniques, i.e. RANS, URANS and LES are compared to determine their suitability in the prediction of urban airflow and pollutant dispersion process. The CFD codes are evaluated against wind tunnel experimental data, and it is observed that LES although more computationally expensive, produces the most accurate and reliable results because it resolves the turbulent mixing process in the flow field. URANS, albeit solving for the transient solution, fails to account for the unsteady fluctuations and hence is not an appropriate replacement for LES.

[1]  F. Antun,et al.  Lebanon , 1992, International psychiatry : bulletin of the Board of International Affairs of the Royal College of Psychiatrists.

[2]  Rex Britter,et al.  Flow and Pollutant Dispersion in Street Canyons using FLUENT and ADMS-Urban , 2008 .

[3]  Bodo Ruck,et al.  Influence of trees on the dispersion of pollutants in an urban street canyon - experimental investigation of the flow and concentration field , 2007 .

[4]  Aaas News,et al.  Book Reviews , 1893, Buffalo Medical and Surgical Journal.

[5]  Michael Schatzmann,et al.  BACKGROUND AND JUSTIFICATION DOCUMENT TO SUPPORT THE MODEL EVALUATION GUIDANCE AND PROTOCOL , 2007 .

[6]  Riccardo Buccolieri,et al.  Numerical simulation of atmospheric pollutant dispersion in an urban street canyon: Comparison between RANS and LES , 2011 .

[7]  Riccardo Buccolieri,et al.  Analysis of local scale tree-atmosphere interaction on pollutant concentration in idealized street canyons and application to a real urban junction , 2011 .

[8]  Miss A.O. Penney.  (b) , 1974, The New Yale Book of Quotations.

[9]  Jiyuan Tu,et al.  Computational Fluid Dynamics: A Practical Approach , 2007 .

[10]  Bodo Ruck,et al.  On the Impact of Trees on Dispersion Processes of Traffic Emissions in Street Canyons , 2009 .

[11]  Andy Chan,et al.  Numerical simulation of dispersion in urban street canyons with avenue-like tree plantings: Comparis , 2011 .

[12]  Salim Mohamed Salim,et al.  Wall y+ approach for dealing with turbulent flows over a wall mounted cube , 2010 .

[13]  R. Britter,et al.  FLOW AND DISPERSION IN URBAN AREAS , 2003 .

[14]  Anju Vyas.  Print , 2003 .

[15]  Y. Tominaga,et al.  Numerical simulation of dispersion around an isolated cubic building: Model evaluation of RANS and LES , 2010 .

[16]  Riccardo Buccolieri,et al.  Dispersion study in a street canyon with tree planting by means of wind tunnel and numerical investigations – Evaluation of CFD data with experimental data , 2008 .

[17]  Weeratunge Malalasekera,et al.  An introduction to computational fluid dynamics - the finite volume method , 2007 .