2011 Volume 25 Issue 3 Pages 237-244
Particle image velocimetry and ultrasound velocity profiling have around 25 years in history from their first appearance on literature. The early type of their instruments measures flows only at very slow speed in simple spatial structure. The rapid advances in computing tip above silicon cycle escalated them onto the stage of wide applications from fundamental study in fluid mechanics to major experimental tool for designing, managing, and evaluating of thermo-fluid phenomena. Extension to multiphase flow in the last decade is making their big news both in science and engineering researches. This article reports on the current topics and technical problems in multiphase flow toward next generation.