A new ray tracing model for aero-optical effect simulation of laminar flow field surrounding highly supersonic projectile with cone shape head

We present the apparent optical performance variation of an infrared sensor caused by laminar flow field surrounding a highly supersonic projectile with cone shape head. An optical ray tracing model was constructed and numerical simulations of the aero-optical effects were performed by computational fluid dynamics (CFD) analysis and isodensity surface based ray tracing computation. To maximize modeling and computation efficiency, the number of sampling isodensity layers was reduced to less than 5 for improved discretization of the inhomogeneous gradient index (GRIN) media. Using this method, the simulation results show that the BSE is smaller than about 2.8 arcsec when the projectile flies at 25, 35, 50 km in altitude, Mach 4, 6 in speed, and 0°, 10deg; in angle of attack. The technical details and implications of the optical ray tracing model are presented together with the simulation results.