On the deformation and drag of a type-A multiple drop at low Reynolds number

Abstract

The dynamics of a perfectly symmetric type-A multiple drop is studied. Up to first order in Reynolds number a force balance predicts the size ratios of the two constituents of such a drop to be unique for each system. Inertial effects are shown (a) to be destabilizing and (b) to exclude the possibility of obtaining perfectly concentric type-A droplets in a diffusion column. This latter conclusion is strengthened further by the sedimentation results.