3-D PTV - Preview of Techniques and Applications

3-D PTV is the abbreviated name of the three-dimensional particle tracking velocimetry. The PTV technique is one of the particle imaging velocimetry (so called PlY) which has been recognized as one of the most advanced techniques for fluid flow velocity measurement because of its strong points of (1) instantaneous whole field (multi-point) velocity measurement, (2) contact free measurement, (3) fullyautomatic measurement, and (4) low cost measuring system in comparison with the other one point measurement techniques such as LDV (Laser Doppler Velocimeter) and hot wire anemometry, Although the two-dimensional (2-D) PIV techniques including PIV have become more and more popular and are employed in many laboratories and practical industries, the three-dimensional (3-D) PIV techniques including 3-D PTV have not been completed yet. The principle of the PIV technique is based on the image analysis of particles which are put in the fluid to visualize the fluid flow. PIV has been developed with the supporting backgrounds of the advanced techniques of video, television, image processor, computer and laser as the lighting system. The present report was prepared for the text of "the International Workshop on 3-D PIV" which was organized by Dr. J. C. Kent and held at Ford Research Laboratory, Dearborn, U.S.A. on 14-17 August, 1994. One of the author (F. Yamamoto) was one of the invited speakers at the workshop and explained( 1) his groups 3-D PTV technique, so called binary image cross-correlation method,(2) stereo pair matching technique, and(3) future aspects of 3-D PlY, entitled "Challenges in 3-D Flow Field Measurements". The present report describes the preview of the most recent research achievements done by the top leaders in the field of PIV and proposes new problems in order to promote successful development of 3-D PTV technique and stimulate innovative science and engineering.