Dispersion of pollutants in street canyon under traffic induced flow and turbulence

A 3-D Eulerian-Lagrangian approach to moving vehicles is presented that tak es into account the traffic induced flow rate and turbulence. The method is applied to pollutants dispersion in a street canyon. The approach is based on CFD calculations using Eulerian approach to the continuous phase and La grangian approach to the,discrete phase" of moving objects vehicles. A comm ercial CFD code StarCD was used into which the Lagrangian model was integra ted. As an example a street canyon is taken into consideration. It has the length of 50 m and the aspect ratio of 1.27. The speed of wind was assigned values of 4, 7 and 12 m/s at the altitude of 300 m. The total height of th e domain is 115 m. In the study different traffic situations are considered , namely one-way and two-way traffic with different traffic rates per lane. The predictions show that different traffic situations affect pollutants d ispersion in the street canyon and that there are also differences in the p ollutants dispersion in case of one- and two-way traffic.