On the urban geometry generalization for CFD simulation of gas dispersion from chimneys: Comparison with Gaussian plume model

This article is a contribution to the geometry generalization for computational fluid dynamics (CFD) simulations of gas dispersion in urban areas. The CO₂ emission from a natural gas-fueled thermal power plant is simulated using different generic urban patterns. The buildings distribution, the built density and the height of the buildings were analyzed. Both buildings distribution and built density did not show significant effect on the gas concentration over the city, whereas the average height of the buildings shows a clear influence on the vertical profile of the gas concentration. The results of the general patterns were compared with a real city (Munich, Germany), obtaining agreement between both generalized and real city geometries. Additionally, the vertical profiles of gas concentration were compared with the Gaussian plume model, and a new equation for computing the vertical dispersion parameter is proposed for urban environments as a function of the averaged buildings height.