Comparison of les and durbin type k-ε model for gas diffusion in weak wind region behind a building

Flow and diffusion fields around a building were predicted by LES and Durbin type k-ε model. The prediction accuracy of the both models was assessed by comparing their results with those obtained by wind tunnel test. The results of LES showed good agreement with experimental data in terms of mean wind velocity, turbulence statistics and mean gas concentration, while the significant differences were observed between the results of the experiment and the Durbin type k-ε model concerning the flow and diffusion fields in the wake region behind the building. This is mainly due to the fact that the periodic motions caused by the vortex shedding were not reproduced by this model.