Numerical simulation of turbulence and transport of fine particulate impurities in street canyons

The LES-model combined with the Lagrangian particle transport procedure is used to simulate the turbulence and propagation of particulate impurities in urban environment. A simplified geometry for a periodic sequence of urban canyons is considered in the case of the transverse mean wind direction. A number of the Lagrangian methods are tested and compared with the Eulerian methods of scalar concentration transport. The obtained numerical results are also compared with experimental data. The transport of heavy carbon particles up to seventy microns in diameter is numerically studied. The regularities in the impurity transport by the turbulence and large eddies are revealed on the basis of the analysis of Lagrangian particle trajectories.