Velocity Field measurements using bubble tracers in a cavitation tunnel

Abstract

As the tracers for PIV (Particle Image Velocimetry) can cause damages on the inner equipment's sensors or tough cleaning works after experiments, PIV measurements have been excluded, especially in a cavitation tunnel containing too much water, even though they have efficient potentials on the quantitative visualization and analysis of flows around the underwater body. The objective of present study is to investigate the possibility of PIV using tracers of bubbles naturally generated in a cavitation tunnel. The bubble can be grown from the nuclei melted in the water of tunnel and the size of bubbles is changed by varying the tunnel pressure. Since the trace ability and appropriate size of tracer are so important for PIV techniques, the characteristics of bubbles as tracer should be found out in the viewpoint of trace ability and bubble size with the variation of flow speed and tunnel pressure., Copyright ？ 2008 by The International Society of Offshore and Polar Engineers (ISOPE).