CFD modeling of air pollution dispersion in complex urban area

Abstract

With the ultimate goal of prediction species dispersion and pollution transport using computational fluid dynamics (CFD), this paper evaluates the performance of two different modeling approaches Reynolds-averaged Navier–Stokes (RANS) standard k-e, and Large Eddy Simulation (LES) applied to pollutant dispersion in an actual urban environment downtown Hannover. The modeling is based on the hypothesis neutral atmospheric conditions. LES is chosen to capture the effects of velocity randomness of the pollutants convection and diffusion. Computer-aided design, CAD, of Hannover city demonstrating different topologies and boundaries conditions, are cleaned, then in fine grids meshed. Pollutants are introduced into the computational domain through the chimney and/or pipe leakages. Weather conditions are accounted for using logarithmic velocity profiles at inlets. Simulations are conducted on 80 cores cluster for several days. CH4 distributions as well as streamlines and velocity profiles conducted on reasonable results. The major interest of presenting work is that it involved a large group of real buildings with a high level of details that can represent the real case of the problem.