Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 29, 2018 - November 30, 2018
The use of bubbles as a way of reducing skin frictional drag has long been a focus for engineers. The existence of gas bubbles into a boundary layer of a liquid phase has multiple different impacts on the original flow structure. In the present study, drag force was measured acting on the elliptic cylinder when it was accelerated under three conditions. The cylinder was immersed in tap water and in tap water with microbubbles, and two types of microbubble generator (slit type and pressurized dissolution type) were used in this experiment. The cylinder was accelerated from 0 to 4.2 or 6.3 cm/s. It was shown that the presence of microbubbles reduced drag on the cylinder in tap water. Microbubbles generated by the slit type that had stronger zeta potential was more effective than that by the pressurized type.
