Examining the κ-ϵ model by means of a wind tunnel test and large-eddy simulation of the turbulence structure around a cube

The κ-ε{lunate} turbulence model and large-eddy stimulation (LES) are used to predict the 3D flow field around a surface-mounted cubic model. Comparison of the results from κ-ε{lunate} modelling with those from a wind tunnel test reveals several significant discrepancies. The results of LES agree fairly well with the experimental data. The shortcomings of the κ-ε{lunate} model are examined precisely, using the numerical data given by LES. The major inaccuracies of the κ-ε{lunate} model are its overestimation of the value of the turbulence energy κ around the frontal corner and its understimation of the value of the lateral component of normal stress <u₂′u₂′> in the recirculation region behind the model. The first inaccuracy is concerned with the expression for evaluating the turbulence production of κ under eddy viscosity modelling and the second is caused by the unsuccessful reproduction of Karman's vortex street.