A numerical investigation of compressible flow in a curved S-duct

Subsonic flow of a compressible, viscous fluid through a compact, high-offset S-duct is studied using numerical simulation of the Reynolds-averaged Navier-Stokes equations on an unstructured grid in three spatial dimensions. Results are compared to existing experimental steady-state data to validate the computed solutions. Effects of grid resolution, including boundary layer spacing and localized refinement are considered resulting in recommendations for best practices in developing grids for future S-duct studies. Methods of sampling steady-state pressure data are compared, resulting in a clearer understanding of the ability of the standard 40-probe instrumentation to capture the flow features. Simulations are conducted using the Spalart-Allmaras, Menter SAS and two-equation k − ε/k − ω turbulence models to determine which models best capture the relevant flow features. None of the tested turbulence models produces a solution which is clearly a better fit to the experimental data in comparison to the other turbulence models