Comparison of Transonic Buffet Over Several Airfoil Geometries using URANS
In this study, we apply computational fluid dynamics (CFD) to compare transonic buffet over several airfoil geometries and flow conditions. Transonic buffet is a fluid instability in which a recompression shock oscillates over the upper surface of an airfoil. Buffet shows significant sensitivity to both numerical models and parameters as well as physical conditions - this work explores sensitivities to geometry and operating conditions. We look at trends with respect to angle of attack, Reynolds number, and Mach number over a NACA0012, OAT15A, and RA16SC1, chosen for the availability of experimental data. We expand on this comparison by modifying the thickness and camber of an airfoil incrementally to produce a trend in buffet onset point with respect to thickness and camber. We approach the problem in ANSYS Fluent with an Unsteady Reynolds-Averaged Navier-Stokes (URANS) model, using the Spalart-Allmaras turbulence closure. This study draws comparisons among the airfoils’ results and also between our computations and the literature.
