High-speed interferometric measurement of aerodynamic phenomena

The cross-sections of high-speed aerodynamic phenomena are presently measured by means of a system that interferometrically ascertains optical path length changes with high spatial resolution. Attention is given to the optical disturbance through an aerocurtain, and to the shock wave produced by a hypersonic projectile. While the slowest repetition rate of the laser, camera, and data recorder determines the time-frame rate, the combination of the camera and data recorder determines the spatial resolution. The technique is the spatial equivalent of phase-shifting interferometry. The real-time hardware employed is discussed.