The motion of an inviscid drop in a bounded rotating fluid

The motion of a buoyant inviscid drop rising vertically along the rotation axis of a rapidly rotating low viscosity tluid bounded above and below by rigid horizontal boundaries is considered in the case that the drop is circumscribed by a Taylor column that spans the entire fluid depth. Both the shape and steady rise speed of the drop are deduced as a function of the interfacial tension. The analysis demonstrates that the drop assumes the form of the prolate ellipsoidal figure of revolution which would arise in the absence of any relative motion in the surrounding fluid. The hydrodynamic drag on the drop follows simply from the analysis of Moore and Saffman [J. Fluid Mech. 31,635 ( 1968) 1, who considered the equivalent motion of a rigid particle. The rise speed of a deformed inviscid drop is approximately one-half that of an identically shaped rigid particle; in particular, the rise speed of a spherical inviscid drop is 0.41 that of a rigid sphere.