Abstract
An optical measurement device of microbubble void fraction was developed especially aiming at the full-scale test. The strut with a side window was installed on the hull surface of M.S. Seiun-maru.
A CCD camera in the strut took pictures of microbubbles through the side window under a stroboscopic light. The image of microbubbles was processed by a PC using a picture processing software.
The void fraction distribution has a peak at the distance of 5-10mm from the hull surface. The void fraction also changed much according to the ship speed. Such the data is invaluable for the research on the turbulent frictional drag reduction of a ship by microbubbles.
