Abstract
Adding particles or bubbles to a flow dramatically complicates characterization of the flow and quantitative measurement techniques are expected to elucidate the mechanisms of two-phase flow, especially multi-scale dependency on its structure. The authors have developed visualization techniques such as particle image velocimetry and particle tracking velocimetry, which are applicable to fluid flows with the range from macro, mezzo to micro/nanoscale. From a viewpoint of macroscale, the energy transfer from large to small eddies in a turbulent two-phase flow has been quantitatively investigated by a high-speed CCD camera and a laser. While the effect of electric field on a microchannel flow has been analyzed by an optical measurement system with a spatial resolution of a few μm. Quantitative visualization will advance our understanding of the interactions between two phases, which are not yet fully understood.
