PARTICLE TRAJECTORY SIMULATION OF DISPERSION AROUND A BUILDING

Lagrangian stochastic (LS) models have shown to be a powerful techniqu e to calculate pollutant dispersion in complex Bows. In this work, a t hree-dimensional LS model of dispersion has been tested by means of a comparison with EPA wind-tunnel observations of a buoyant plume in the vicinity of a building (Snyder, 1992, FMF Internal Report, U.S. Envir onmental Protection Agency, Research Triangle Park, North Carolina). T he model is based on the well-mixed criterion (Thomson, 1987, Journal of Fluid Mechanics 180, 529-556) and is able to evaluate dispersion in inhomogeneous, skew turbulence. The input flow field around the build ing has been carried out by handling EPA data (Snyder and Lawson, 1993 , FMF Internal Report, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina). The concentration field predicted by t he present model and Thomson's (1987) model have been compared with EP A observations in the same configuration. The dispersion of a tracer e mitted from a line source, located at ground level upwind and downwind of the building, has also been investigated, showing the effects of t he vortex structure on the mean concentration field. (C) 1997 Elsevier Science Ltd.