UNSTEADY SURFACE-VELOCITY FIELD MEASUREMENT USING PARTICLE TRACKING VELOCIMETRY

A method has been developed for obtaining surface-velocity fields in u nsteady 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 r elatively wide areas. Results are presented from its application to fl ows around conical model islands with uniform sloping sides from which strong vortex shedding occurs. To allow an assessment of accuracy, si multaneous LDA measurements were taken in the wake of an island and co mparisons of velocity prediction are presented.