Subsonic Aerodynamic Characteristics of a Spinning Projectile at High Angles of Attack

The aerodynamics of a spinning projectile in subsonic flow at angles of attack up to 90° were investigated using force balance measurements, particle image velocimetry (PIV), and numerical flow simulations. Experiments were conducted in a wind tunnel at Mach 0.086, with a diameter-based Reynolds number of [Formula: see text], and spin-to-freestream velocity ratios up to 2.1. Force balance data were collected for normal force, Magnus force, pitching moment, and Magnus moment across 11 spin rates and angles of attack from 0 to 90°. PIV was employed at selected conditions in five transverse planes along the length of the projectile, and the resulting velocity data were used to reconstruct the corresponding pressure fields. Based on this extensive set of force, velocity, and pressure data, an exhaustive discussion of the flow behavior is provided, revealing three distinct regimes: attached flow up to 20° angle of attack, vortex-dominated flow up to 65°, and separated wake flow at higher angles of attack. Large-eddy simulation (LES) results were in good agreement with the experimental data and were used to validate the pressure reconstruction method and provide additional insight into the three-dimensional structure of the flow.