Comparison of various revised k-ε models and LES applied to flow around a high-rise building model with 1:1:2 shape placed within the surface boundary layer

This paper compares computational fluid dynamics (CFD) results using various revised k-ε models and large eddy simulation (LES) applied to flow around a high-rise building model with 1:1:2 shape placed within the surface boundary layer. The first part of the paper examines the accuracy of various revised k-ε models, i.e. LK model, MMK model and Durbin's revised k-ε model, by comparing their results with experimental data. Among the computations using various revised k-ε models compared here, Durbin's revised k-ε model shows the best agreement with the experiment. The reason for the good performance of Durbin's model is discussed on the basis of 'Realizability' of predicted results. The second part of the paper describes the computations based on LES with and without inflow turbulence applied to the same flowfield. The results are compared with those of the experiments and Durbin's k-ε model in order to clarify the effect of velocity fluctuations on prediction accuracy of time-averaged velocity fields around the building. Special attention is paid to prediction accuracy for reproducing flow behind a building. The LES results with inflow turbulence show generally good agreement with experimental results in terms of the distributions of velocity and turbulence energy in this region. This improvement is mainly due to the fact that the periodic velocity fluctuation behind the building is well reproduced in LES.