S0501-2-1 Flow Birefringence Measurement around Small Bubbles under Pressure-oscillating Field

Abstract

We have developed the Pressure-Oscillating Defoaming for removing air bubbles from shear-thinning fluids. When two air bubbles are set vertically in a quartz cell filled with shear-thinning fluids, the lower-bubble rises faster than the upper bubble under pressure-oscillating field generated by pressing a rubber sheet at the bottom of the cell^<(1)>. However, this mechanism of the behavior has not been completely understood. By using liquid with a good photoelastic correlation and rheological property similar to the UCM model^(2), we try measuring the stress in the vicinity of small bubbles under pressure-oscillating field. In this study, a relation between the retardation and the distance from the bubble surface was measured experimentally.