A Computational and Experimental Study Of Pollution Dispersion In An Isolated Street Canyon

This paper presents experimental and computational investigation of the dispersion mechanisms of a passive-type tracer gas, done in the scaled, three-dimensional model of a street canyon. At a low wind speed of 1.67m/s and neutral atmospheric conditions, dispersion of pollutant has been investigated within an isolated street canyon at an aspect ratio of 1 for perpendicular wind orientation (90). Vehicle emissions are simulated with the line source placed in the middle of the street emitting tracer gas mixture of 5% Acetylene and 95% Nitrogen at a uniform rate with online tracer gas sampling in the gas chromatograph. These experiments have been simulated numerically using CFD-code Fluent for standard, realizable and RNG k-ε turbulence models. A reasonable qualitative agreement has been observed between the CFD predicted dispersion and the wind tunnel results, suggesting that CFD might be an appropriate tool to systematically explore the influence of street canyon geometry.