Aero-Optic Effects of a Wing Tip Vortex

For an airborne optical system carried by a helicopter, aero-optic aberrations originate primarily from blade tip vortices that pass through the system field of view; these aberrations result from the reduced pressure and density in the vortex cores and the associated variations in the index-of-refraction. Using the weakly compressible model (WCM) previously developed at Notre Dame, aero-optic effects for realistic tip-vortex flows are computed using the Lamb-Oseen vortex model as well as experimental velocity fields, and compared to measured wavefronts. Scaling relations are developed that enable the prediction of the aero-optic aberrations for full-scale flight vehicles.