Large-scale particle tracking velocimetry with multi-channel CCD cameras

This paper presents a large-scale particle tracking velocimetry (LSPTV) system for measuring surface velocity in vast unsteady flows. The system consists of a flexible number of one-computer-six- camera working units connected via local network or the internet. Multiple zero-tilting cameras are used to increases the field of view with minimum perspective distortions. External synchronization of video outputs of all cameras facilitates uninterrupted image acquisition within the system. Effectiveness and efficiency of the multi-channel LSPTV are enhanced by optimizing illumination, flow seeding, image acquisition and correction, tracer identification, particle matching, and post-processing. The capacity of the LSPTV was demonstrated in the measurement of physical model flows for the Three Gorges Project.