Numerical Investigation of the Flow Field Around a Low Rise Building Using LES Technique

In this research the flow field obtained by LES technique is compared with laboratory data measured around a low rise building model with 1:1:0.3 (length: width: height) aspect ratio. The results also are compared with some other turbulence models. The turbulence models include standard k-epsilon, Durbin's revised k-epsilon (DBN), and LRR Reynolds stress models (RSM). Firstly the limitations of the mentioned turbulence models are described for capturing the recirculation zone above and behind of the building model. Among the RANS models, Durbin's revised model with low Reynolds type of the boundary condition predicts the flow field around the building better compared with other RANS models. The Smagorinski and WALE models among SGS models of LES were employed for the simulation of flowlield around the building. The LES results show generally a better agreement with experimental data compared with RANS models for the streamwise velocity at the roof and behind of building. This improvement is mainly due to the fact that the periodic velocity fluctuation behind the building is well reproduced in LES.