NASA Technical Memorandum 102048 A Vector Scanning Processing

A VECTOR SCANNING PROCESSING TECHNIQIJE FOR PULSED LASER VELOCIMETRY Mark P. Wernet National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohio 4113.5 and Robert V. Edwards Case Western Reserve University Dept. of Chemical Engineering Cleveland, Ohio 44106 by Pulsed laser sheet velocimetry yields non-intrusive measurements of two-dimensional velocity vectors across an extended planar region of a flow. Current processing techniques offer high precision (1%) velocity estimates, but can require several hours of processing time on specialized array processors. TJnder some circumstances. a simple. fast. less accurate ( ~ 5 % ) , data reduction technique. which also gives unambiTuous velocity vector information is acceptable. In this work, we examine a direct space domain processing, technique. The direct space domain processing technlque was found to be far superior to any other techniques known, in achieving the objectives listed above. It employs a new data coding and reduction technique, where the particle time history information is used directly. Further, it has no l S O o directional ambi uity. A complex convection vortex flow was recorded an f completely processed in under 2 minutes on an S03S6 based PC, producing a 2-D velocity vector map of the flow field. Hence, using this new space domain Vector Scanning (VS) technique, pulsed laser velocimetry data can be reduced quickly and reasonably accurately, without specialized array processing hardware.