Time-resolved particle image velocimetry used in the investigation of cavitation bubble dynamics

The temporal evolution of the velocity field of an unsteady fluid flow can be tracked by combining particle image velocimetry and high speed photography. We used this technique to investigate the flow around cavitation bubbles during their collapse near a solid boundary. The light source was an argon laser with an external acoustooptic deflector which produces series of short pulses. Using a drum camera for high speed photography, we achieved a temporal resolution of 10 kHz and a spatial resolution of better than 2 points/ mm(2). Velocities could be determined without directional ambiguity in a range from 2 to 30 m/s.