On the evaluation of linear and non-linear models using DNS data of turbulent channel flows

in this paper, a priori and a posteriori analyses of algebraic linear and non-linear models are carried out in order to compare their ability to predict near wall turbulent flows. tests were done using data from a direct numerical simulation (dns) of a plane channel flow for three reynolds numbers, based on the friction velocity, reτ = 180, reτ = 395 and reτ = 590 . these models include the linear standard k - ε model, the linear v2- f (manceau et al., 2002) and the non-linear model of shih (shih et al., 1995). the results obtained are then compared with the dns data of moser et al. (1999). the comparisons are shown for the mean velocity profile, components of the reynolds stress tensor, the turbulent kinetic energy (k), and the dissipation rate (ε). the results suggest that the v2 - f is an efficient model to capture the turbulent shear stress component of the reynolds stress near wall flows. however, it is unable to predict correctly the level of anisotropy between normal components of the reynolds stress tensor. furthermore, it is shown that the presence of non-linear terms in a turbulent model improves the ability to predict the anisotropy