Effect of Fins on the Mean Wake of a Generic Supersonic Projectile

A numerical study of a generic projectile with a solid base at Mach 2 is used to highlight the impact of fins on the wake across a range of roll and pitch angles from zero to 12 deg. To accommodate this wide range of parameters, with and without fins, the Reynolds-averaged Navier–Stokes equations are solved with a realizable Formula: see text turbulence model and validated against available experimental data. The effects of fins on the wake are characterized by a detailed analysis of the emergent shock and vortical structures, as well as the consequent aerodynamic loads. At a zero angle of attack, the fin trailing edge introduces new shocks/expansions that fundamentally alter the shape and strength of the recompression shock. Pitch and roll further modify the shocks and vortices, which can now be distinguished as forebody, wingtip, and trailing-edge components. At certain pitch and roll conditions, wingtip vortices bound and split the recompression shock into multiple sections, changing their inception and subsequent trajectory. Under pitch conditions, fins effectively flip the trailing-edge vortices, which now form on the lower side of the base surface rather than the upper side, with a reversal of streamwise vorticity direction. The results identify the main features of interest for further exploration with scale-resolving simulations.