抄録
The interaction between the bubble motion and its surrounding liquid motion through a collision of a pair of bubbles in a rest water column was experimentally investigated. A pair of hypodermic needles and a bubble generator utilizing pressure oscillation were employed in order to exactly extract and highly reproduce the interaction between the liquid-phase motion and bubble motion. The recursive correlation PIV technique made it possible to obtain the accurate velocity field of the surrounding liquid motion of a pair of bubbles. The vorticity field around a pair of bubbles was calculated from the results of velocity field. First, the bubble motion of a pair of bubbles is discussed. We focus on the bouncing as bubble motion. After the bouncing, the horizontal velocity of each bubble obviously decelerated. Second, the surrounding liquid motion of a pair of bubbles is discussed. The magnitude of vorticity around a pair of bubbles just before the bouncing was larger than that around a single ascent bubble. The interaction between each wake and the flow between bubbles yielded it. The vortex which consists of the vorticity at the rear of each bubble was found to reverse its direction of rotation during the bouncing.
