Comparison of various types of k–ε models for pollutant emissions around a two-building configuration

The dispersion of pollutants exhausted from a building roof stack located in a tower was investigated using various types of k–ε turbulence models, i.e., a standard k–ε model, a RNG k–ε model and a realizable k–ε model, all implemented using Fluent software. In order to determine the turbulence model that best helped reproduce pollutant plume dispersion, the most critical case was considered, namely, when wind blew perpendicularly towards the upstream tower, then placing the building in its wake. When numerical results were compared to wind tunnel experiments, it was found that the realizable k–ε turbulence model yielded the best agreement with wind tunnel results for the lowest stack height, while for the highest stack height, the RNG k–ε turbulence model provided greater concordance with experimental results. The realizable k–ε model was the only model able to provide the correct trend for the concentration distribution in the lower region between the two buildings; however, none of the models reproduced the trend in the upper regions. The standard k–ε model was generally found to be inadequate for reproducing vertical concentration distribution.