Experimental and numerical verification of similarity concept for dispersion of car exhaust gases in urban street canyons

In urban conditions, car exhaust gases are often emitted inside poorly vent ilated street canyons. One may suppose however that moving cars can themsel ves produce a certain ventilation effect in addition to natural air motions . Such ventilation mechanism is not sufficiently studied so far. A similari ty criterion relating the vehicle- and wind-induced components of turbulent motion in an urban street canyon was proposed in 1982 by E. J. Plate for w ind tunnel modelling purposes. The present study aims at further evaluation of the criterion and its applicability for a variety of wind and traffic c onditions. This is accomplished by joint analyses of data from numerical si mulations and wind tunnel measurements.