Jaroslav Katolicky

Disperion of Pollutants under Traffic Induced Flaw and Turbulence in Two Street Canyons Forming an Intersection

To correctly predict pollutant dispersion around traffic constructions like road tunnels, large city crossroads and/or street canyons, relations between sources and receptors must be established. In this procedure, traffic plays a significant role. Moving vehicles enhance both microand largescale mixing processes in the environment by inducing additional turbulence and partly by entraining masses of air in the direction of vehicle movement. In this study authors focus on traffic and its impact on the pollutants dispersion in two street canyons that form a perpendicular intersection. A model based on Eulerian Lagrangian approach to moving objects has been developed (Jicha et al., 2000) and integrated into a commercial CFD code StarCD.

MODELLING OF POLLUTANTS DISPERSION FROM A CITY ROAD TUNNEL

An outlet portal of a city road tunnel is one of crucial point sources of pollutants to be taken into account when modeling dispersion of pollutants within a city. Namely in case of local scale modeling a correct knowledge of velocity and concentration profiles at the outlet portals may play a non-negligible role. And these profiles are established in a dominant way by the traffic density and speed. In the first part of the paper we are going to present a new Lagrangian - Eulerian approach to moving vehicles througout a traffic tunnel and as a result to give values of flow rate entrained into and out of the tunnel and velocity and concentration profiles at the outlet tunnel portal. In the second part of the paper, dispersion of pollutants from the Plabutsch highway tunnel in Graz (Austria) is predicted for various boundary conditions.