LASER VELOCIMETER SYSTEMS ANALYSIS APPLIED TO A FLOW SURVEY ABOVE A STALLEDWING

摘要

A laser velocimeter operating in the backscatter mode was used to survey the flow above a stalled wing installed in the Langley high-speed 7- by 10-foot tunnel. Polarization was used to separate the two orthogonal velocity components of the fringe-type laser velocimeter, and digital counters were used for data processing! The velocities of the kerosene seed particles were measured with less than 2-percent uncertainty. The particle velocity measurements were collected into histograms.nThe flow-field survey was carried out above an aspect-ratio-8 stalled wing with an NACA 0012 section. The angle of attack was 19.5°, the Mach number was 0.49, and the Reynolds number was 1.4 x 106. The flow field was characterized by the periodic shedding of discrete vortices from near the crest of the airfoil.