CFD simulations of pollutant dispersion in a street canyon: Impact of ideal versus realistic source emissions

Pollutant dispersion is of great relevance for people living in urban areas. Idealized point and line sources are commonly used to reproduce traffic emissions in street canyons. However, a limited number of studies focus on the usage of realistic sources, such as real car geometries, which can influence the flow characteristic thus the pollutant distribution inside the canyon. This is the goal of the present paper for which Computational Fluid Dynamics (CFD) simulations were performed on a street canyon to investigate the impact of an ideal point and a realistic source. At the first stage, CFD simulations were performed with an ideal point source and validated with wind-tunnel (WT) data. At the second stage, CFD simulations were carried out on a street canyon using a realistic source. The result shows that the distribution of V*, K*, and C* inside the canyon can be strongly affected by car geometry.