Investigation of various non-linear eddy viscosity turbulence models for simulating flow and pollutant dispersion on and around a cubical model building

Abstract

Prediction accuracy of various non-linear eddy viscosity turbulence models for simulating flow and pollutant dispersion on and around an isolated cubical model building with a rooftop vent within the neutral turbulent boundary layer was investigated. For this purpose, three types of quadratic along with three cubic non-linear models were employed and simulation results were compared with the available wind tunnel measurements and linear revised k-ɛ models. They were different from the preceding simulations which have only concentrated on the wind flow field around buildings. Detailed analysis of dispersion mechanisms based on convective and turbulent diffusion mass fluxes indicated that concentration distributions predicted by non-linear models at the sidewall improved significantly relative to the traditional standard k-ɛ and linear revised k-ɛ models which was due to larger lateral turbulent diffusion. Moreover, thorough analysis of these fluxes underlined the prominent capability of non-linear models in capturing the anisotropy of turbulence and verified the importance of recirculation regions in the pollutant dispersion around a model building. Among the various non-linear models under study, cubic models of Craft et al. and Ehrhard and Moussiopoulos provided the best performance as compared with the other numerical and experimental data.