2042 フォトクロミック染料による気泡後流中の乱流混合の研究

抄録

Turbulent mass mixing caused by a rising bubble in a still fluid in a circular pipe is investigated by visualization and noninvasive concentration measurement using a photochromic dye. Visualized dye patterns indicate that the dye was mixed by vortex motions in the turbulent wake and this phenomenon is different from that of low Reynolds numbers where the dye was drawn straightly along the laminar wake of the bubble. The concentration distribution deduced from the dye image using Lambert-Beer's law shows rather isotropic mixing in longitudinal direction. Turbulent diffusion coefficients calculated by the temporal changes in the concentration distribution are compared to those of a solid sphere.