Lift Coefficients of Clean Ellipsoidal Bubbles in Linear Shear Flows

Abstract

The lift force acting on an ellipsoidal bubble is known to change its sign, depending on the bubble aspect ratio. The lift reversal has often been modeled in terms of the Eötvös number defined by using the bubble major axis to account for the deformation effect on the negative lift component. This paper presents a physically reliable scaling accounting for the two mechanisms in competition related to the two sources of vorticity: the lift controlled by the shear flow and contribution from the interfacial vorticity source. This scaling is used for developing a correlation that makes possible the lift modeling with the reversal.