The viscosity distribution around a rising bubble in shear-thinning non-newtonian fluids

the viscosity distribution of the liquid around a rising bubble in carboxymethyl cellulose (cmc) aqueous solutions was measured experimentally by particle image velocimetry (piv). the effect of the concentration of cmc solutions on the viscosity distribution around a bubble and the coupling relations between the viscosity field, flow field and shear stress field were also studied. results indicated that the specific viscosity (non-dimensionalized by η0) decreases with the increase in cmc solution concentration due to a shear thinning effect. within the experimental range, similar viscosity distributions of liquids around a rising bubble were found: a hollow cylindrical low viscosity region around the bubble wake and a high viscosity region in the central bubble wake.