Evaluation of one- and two-equation low-Re turbulence models. Part II - Vortex-generator jet and diffusing S-duct flows

This second segment of the two-part paper systematically examines several turbulence models in the context of two flows, namely a vortex flow created by an inclined jet in crossflow, and the flow field in a diffusing S-shaped duct. The test cases are chosen on the basis of availability of high-quality and detailed experimental data. The tested turbulence models are integrated to solid surfaces and consist of: Rodiʹs two-layer k-(omega) model, Wilcoxʹs k-(omega) model, Menterʹs two-equation shearstress-transport model, and the one-equation model of Spalart and Allmaras. The objective of the study is to establish the prediction accuracy of these turbulence models with respect to three-dimensional separated flows with streamline curvature. At the same time, the study establishes the minimum spatial resolution requirements for each of these turbulence closures, and identifies the proper low-Mach-number preconditioning and artificial diffusion settings of a Reynolds-averaged Navier-Stokes algorithm for optimum rate of convergence and minimum adverse impact on prediction accuracy.