Aero-Optical Measurement in Shock Wave of Hypersonic Flow Field

Hypersonic flow field around a flight vehicle has density fluctuating elements such as shock wave and boundary layer. Since refractive index of light is related to density of medium, light propagation path changes while passing through the flow field. Influence of flow field property on optical characteristics is called aero-optics. As in Fig. 1, aero-optics distorts the image obtained by an optical instrument on the flight vehicle and degrades light intensity, displaces the position of an object, blurs the image, etc. To avoid these effects, various studies were conducted to relate optical characteristics with flow characteristics and to measure aero-optical aberration.