Experimental Analysis of Supersonic Fin-Wake Interactions

Supersonic flow over axisymmetric projectiles generate complex wake flow physics, which are further influenced by the addition of fins used for stability and control. While necessary, fins introduce Shock-Wave/Boundary-Layer Interactions (SBLI) that complicate the wake dynamics. This study experimentally investigates the effects of a Single-Fin on the near-wake and surface flowfield of an axisymmetric projectile at Mach 3. A fin-free baseline case is compared against configurations with the fin mounted at 0° and 10° angles of attack relative to the freestream, while the projectile body remains at 0°. Schlieren visualization is employed to visualize key flow features, including the fin-tip vortex and shear layer dynamics. Both unsteady and steady surface pressures are captured using fast-response pressure transducers and pressure-sensitive paint. Surface oil flow visualization reveals the SBLI footprint in the fin-wake region, including areas of separation and reattachment. These findings contribute to a deeper understanding of the complex flow physics driving fin–wake interactions and the unsteady aerodynamics of finned projectiles.