Second-moment RANS calculations of turbulent flows in curved channels

A fully elliptic Reynolds-averaged Navier-Stokes (RANS) numerical method has been employed to study the combined effects of the surface curvatures and pressure gradients on steady flows in strongly curved channels and an annular diffuser. Calculations were performed using a near-wall second-order Reynolds stress (second-moment) closure model and an isotropic eddy viscosity model to quantify the effects of Reynolds stress anisotropy due to concave and convex curvatures. Comparison of the numerical results with available experimental data clearly demonstrated the superiority of near-wall second-moment closure models over isotropic eddy-viscosity models.