Numerical investigations of wall-bounded turbulence

Abstract

This article investigates numerically the effects on turbulence in two important flow regimes – fully developed channel flow and flow past a NACA 0012 airfoil, using the commercial software – FLUENT 6.3. The solution accuracy is explored via a sensitivity study of mesh type and quality effects, employing different element types (e.g. quadrilateral and triangular). The significance of this article is to elucidate the effects of enhancement wall treatment and standard wall function on the turbulent boundary layer. Furthermore, three different turbulence models have been utilized in this study (k−ε, re-normalization group (RNG), and shear stress transport (SST) k−ω). The numerical solutions have been compared with available direct numerical simulation (DNS) and experimental data and very good correlation has been achieved. In addition, the statistical turbulence results related to the RNG turbulence model are shown to yield much closer correlation with DNS and experimental data. The effect of Reynolds number (Reτ = 590 and Reτ = 2320) is studied for the channel flow regime. The near wall resolution is examined in detail by controlling in the y+ value. A particularly important objective in this study is to highlight the importance of validation in computational fluid dynamics (CFD) turbulence simulations and sustaining a high degree of accuracy, aspects which are often grossly neglected with industrial CFD software. The authors therefore hope to provide some guidance to applied aerodynamicists utilizing CFD in future studies.