Numerical simulation of turbulent dispersion on a two-way facing traffic road

A Large Eddy Simulation (LES) model was developed to investigate vehicle-induced turbulence and its effect on turbulent dispersion. The instantaneous behaviour of vehicle exhausts and the time-space averaged distributions of flow and concentration statistics on the roadway were estimated. The patterns of mean flow are significantly different between the one-way and the two-way traffic cases. In the vehicle passing area, the standard deviations of the spanwise and the vertical fluctuation velocities are two times larger than the maximum of the mean velocity. The relationship between the growth rate of vertical plume width and the background cross flow was also investigated.