Unsteady surface-velocity field measurement using particle tracking velocimetry

Abstract

A method has been developed for obtaining surface-velocity fields in unsteady flows which is useful for hydraulic model studies. The method is based on the established technique of Particle Tracking Velocimetry (PTV) but unlike other whole-field systems is suitable for use over relatively wide areas. Results are presented from its application to flows around conical model islands with uniform sloping sides from which strong vortex shedding occurs. To allow an assessment of accuracy, simultaneous LDA measurements were taken in the wake of an island and comparisons of velocity prediction are presented.