PERSPECTIVE - SYSTEMATIC STUDY OF REYNOLDS STRESS CLOSURE MODELS IN THE COMPUTATIONS OF PLANE CHANNEL FLOWS

This paper investigates the roles of pressure-strain and turbulent diffusion models in the numerical calculation of turbulent plane channel flows with second-moment closure models. Only high Reynolds number models are considered. Three turbulent diffusion and five pressure-strain models are utilized in the computations. The main characteristics of the mean flow and the turbulent fields are compared against experimental data. All the features of the mean flow are correctly predicted by all but one of the Reynolds stress closure models. The Reynolds stress anisotropies in the log layer are predicted to varying degrees of accuracy (good to fair) by the models. It is found that, contrary to previous assertions, wall-reflection terms are not necessary to obtain the correct Reynolds stress anisotropy in the log-layer. The pressure-strain models determine the level of anisotropy in the log-layer, while the diffusion models strongly influence the rate of relaxation towards isotropy in the outer-layer. None of the models could predict correctly the extent of relaxation towards isotropy of the streamwise and lateral components of the Reynolds stresses in the wake region near the center of the channel. Results from direct numerical simulation are used to further clarify this behavior of the models.