QUANTIFIABLE VORTEX FEATURES OF F-106B AIRCRAFT AT SUBSONIC SPEEDS

Quantifiable vortex features and separated-flow origins have been dete rmined on an F-106B aircraft at 1-g subsonic speeds using the vapor-sc reen technique coupled with image enhancement, photogrammetry, and com puter graphics, In particular, the spatial location of vortex cores, t heir tracks over the wing, and the approximate reattachment locations have been determined as a function of angle of attack and Reynolds num ber, Increasing the Reynolds number generally delays or suppresses lar ge-scale separation and promotes the formation of multiple vortices, w hereas increasing the angle of attack generally promotes the formation of a single vortex system. The multiple vortices observed may likely be attributed to small surface distortions in the wing leading-edge re gion. Comparisons of off-surface determined vortex core location and r eattachment point approximation from the vapor-screen technique are ma de with those from the on-surface techniques of static pressure and oi l now and show generally good agreement. A comparison between quantifi ed vortex features from flight and wind tunnel showed reasonably good agreement over the forward part of the wing for angles of attack from 16 to 20 deg.