B172 せん断流中における単一気泡の三次元形状変化と周囲流動構造 : 気泡形状の非対称性と渦放出の関係

抄録

The dynamics of a single, rising air bubble in a linear shear flow was investigated by high speed and high spatial resolution CCD cameras in a vertical water channel. The present study focused on the influence of forces acting on the bubble and its lateral motion induced by the surrounding flow field. The flow structure in the vicinity of the bubble of 2 to 6mm in diameter was obtained by a PIV/LIF technique, and deformation of the bubble's interface was measured by a shadow imaging technique. It is found that the bubble trajectory was mainly affected by the three-dimensional vortex shedding in the wake. Experimental data of the averaged vorticity at the edge of bubble, the bubble aspect ratio and the curvature of bubble edge showed that the magnitude of vorticity correlates with the bubble shape.