A lagrangian dispersion model for calculating concentration distribution within a built-up domain

A Lagrangian model to study the dispersion of pollutants between urban buildings is described. The flow field is supplied by an objective analysis (Rockle (1990) Ph.D. thesis, Vom Fachbereich Mechanik, der Technischen Hochschule Darmstadt, Germany) and is adjusted to satisfy the continuity equation. From the resulting; mass consistent field the Lagrangian diffusion parameters are eliminated. A 3-D Lagrangian diffusion model in a nonhomogeneous field is applied to calculate the pollutant distribution between the buildings. Several examples are studied and compared to wind tunnel measurements.