Particle Tracking in Space Time Sequences

A particle tracking technique at high particle concentration for the evaluation of flow fields beneath water waves is described. A 14 cm thick light sheet parallel to the main wave propagation direction was used to illuminate small polystyrol seeding particles. The depth of the light sheet was chosen such that the particles stay long enough in the illuminated area to enable tracking. An area of up to 14.0 10.0cm is observed by a digital CCD camera. The recording of continuous image sequences at up to 200 fields/s allow an extensive study of the flow field