Inertia, friction, and angular momentum of an oscillating viscous charged liquid drop under surface tension

The eigenfrequencies of an oscillating viscous charged liquid drop under surface tension are evaluated by assuming potential flow and by solving the linearized Navier--Stokes equation. The kinetic and dissipation energies of this system are obtained via the inertias and friction coefficients and the angular momentum of the drop is calculated. A discussion of the nature of the viscous flow reveals that for small viscosity the curls tend to concentrate close to the surface (boundary layer effect); once having excited the drop, the fluid can come to rest only asymptotically (caused by the curls); and that the potential flow approximation has only a limited validity