Comparative Measurement Between Particle-Strcak and Particle-Tracking Velocimetry

Two types of image-processing velocimetry are tested and compared on the basis of two-dimensional wakes behind a cylindrical body. Both methods make use of tracer particles suspended in water and aim to estimate quasi instantaneous distribution of velocity. However the first one is particle-streak velocimetry which determines velocity vectors from the length and the gradient of particle streaks traced during a given time of exposure, and the second one is particle-tracking velocimetry in which the velocity is determined by a particle pursuit program operating between two sequential image frames. From among a number of pursuit algorithms required for the second velocimetry, the binary correlation method developed by the authors is employed in the present study.