Motion of Single Drops in Linear Shear Flows

Motions of single silicon oil drops rising in linear shear flows of glycerol-water solutions are measured to investigate the effects of the viscosity ratio κ and dimensionless shear rate Sr on drag forces under the conditions of −6.3 ≤ logM ≤ −4.8, 0.94 ≤ κ7.04, 1 < Re ≤ 23 and 3.2 ≤ ω ≤ 6.0 s⁻¹, where M is the Morton number and ω the magnitude of the velocity gradient of the continuous phase. As a result, we confirmed that (1) the drag coefficient C_D of a drop in a linear shear flow takes a higher value than the drag coefficient C_D0 of the same-size drop in a stagnant liquid, (2) C_D/C_D0 increases with Sr, and (3) the augmentation of C_D becomes large as κ increases.