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

The $kapppa-Ε 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 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 model are examined precisely, using the numerical data given by LES. The major inaccuracies of the κ-Ε model are its overestimation of the value of the turbulence energy κ around the frontal corner and its underestimation of the value of the lateral component of normal stress 〈u′2u′2〉 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.