DRAG COEFFICIENT OF A MOVING BUBBLE AND DROPLET IN VISCOELASTIC FLUIDS

Abstract

Effects of viscoelasticity on the drag coefficient for creeping flow past a single air bubble or carbon tetrachloride droplet were investigated. Experimental data were presented for seven dilute aqueous polymer solutions: a 3.5% sodium carboxymethylcellulose solution, a 1.0% polyethylene oxide solution, 0.52%, 0.86%, 2.07% and 2.95% sodium polyacrylate solutions, and a 2.01% methylcellulose solution. A relationship has been obtained by the variational method applied to a Sutterby model fluid, considering the changeability of the shape of fluid spheres. The data for elastic fluids were not fitted by this correlation based on a purely viscous model such as the Sutterby model. This deviation was expressed by the Weissenberg number based on the maximum relaxation time of Spriggs model fluids, and the drag coefficient was correlated with a modified Reynolds number.