Application of the Laser Velocimeter for Trailing Vortex Measurements

This report summarizes a three-year analytical and experimental program to develop a dual-scatter laser velocimeter system to map the flow fields of trailing vortices stemming from the wingtips of flying aircraft. The basic design parameters ascertaining feasibility of the LV-measuring technique are presented. Included is a discussion and evaluation of a newly developed two-dimensional Bragg cell (TDBC) for resolving directional ambiguity. The electronics instrumentation developed for the operation of the TDBC is evaluated in detail. In addition, the development of a direct readout system yielding considerable improvement over the initial instrument is described and evaluated. Prepared in cooperation with ARO, Inc., Tullahoma, Tenn. ARO, Inc., Tullahoma, Tenn.