Evaluation of the traffic producing turbulence within a modelled street canyon using computational fluid dynamics calculations

The motion of vehicular traffic has been identified as a significant source of mechanically-generated turbulent kinetic energy within urban street canyons. As the bulk of free stream wind flow is too weak to penetrate within the street canyon under calm wind conditions, the Traffic Producing Turbulence (TPT) becomes the dominant factor in mixing and diluting traffic-related pollutants. Full scale experiments can not give satisfactory insights into the TPT dynamics, because of the difficulty to study the TPT in isolation from other sources of turbulent kinetic energy within the canyon. For that reason, Computational Fluid Dynamics (CFD) calculations were adopted in order to improve our understanding of the process. Suitability of the CFD calculations in predicting real flow fields was evaluated using wind tunnel data.