DEVELOPMENT OF A DIODE LASER DOPPLER VELOCIMETER WITH DIRECTIONAL SENSING CAPABILITIES-

RECENT DEVELOPMENT OF THE DIODE LASER DOPPLER VELO- CIMETER (DLDV) HAS REVOLUTIONIZED THE USES OF LASER VELOCIMETRY. THE DEVELOPMENT OF A SECOND-GENERATION DLDV THAT HAS DIRECTIONAL SENSING CAPABILITIES AND CAN OPERATE IN A BACKSCATTER MODE IS PLANNED. SUCCESSFUL INCORPORATION OF THESE TWO FEATURES WILL ENHANCE THE THE VERSATILITY, COMPACTNESS, AND OPERATIONAL SIMPLICITY OF THE PROVEN DLDV FOR DEPLOYMENT IN LARGE-FLOW FACILITIES AND IN THE FIELD. SEVERAL TECHNIQUES FOR REMOVING DIRECTIONAL AMBIGUITY, AN INHERENT CHARACTER- ISTIC OF LASER VELOCIMETRY, WILL BE EVALUATED, AND THE MOST PROMISING FOR USE WITH THE DLDV CONFIGURATION WILL BE SELECTED AND TESTED. ONE OF THESE TECHNIQUES WILL BE TO IMAGE THE FOCAL VOLUME ONTO A POSITION-SENSITIVE PHOTODIODE AND TO EXTRACT THE DIRECTIONAL INFORMATION VIA HARDWARE/SOFTWARE SIGNAL PROCESSING. IN ADDITION, THE FEASIBILITY OF OPERATING THE DLDV IN AN ON-AXIS BACKSCATTER MODE WILL BE ASSESSED. FINALLY, A LITERATURE SURVEY WILL BE PERFORMED TO ASSESS THE FEASIBILITY OF OPERATING THE DLDV IN A PULSED MODE TO BOOST THE PEAK LASER POWER BY SEVERAL ORDERS OF MAGNITUDE.