Contribution of Advective and Turbulent Contaminant Transport to the Intersection Ventilation

Abstract

The objective of this experimental study is to determine processes of pollution ventilation above the X-shaped street intersection in an idealised symmetric urban area for several approach flow directions. A unique experimental set-up for simultaneous measurement of the flow velocity and the tracer gas concentration in a high temporal resolution is assembled. Advective and turbulent vertical scalar fluxes are computed from the measured data in a horizontal plane above the street intersection. Vertical turbulent pollution transport was found to be a significant and positive contribution to the total vertical transport of pollutants form the intersection. Prevailing events in vertical scalar and momentum fluxes were determined using quadrant analysis. © Springer Science+Business Media Dordrecht 2014.