Oscillation of liquid drops under gravity: Influence of shape on the resonance frequency

A recently demonstrated technique of aerodynamic levitation has been used t o study the resonance frequency of liquid droplets. A thin pressurized gas layer supports the droplet avoiding any contact with the environment. Due t o the external gravitational field, the measured frequency is different fro m the one predicted Ly the classical models for a spherical drop. An ellips oidal shape has been introduced to take into account the competition betwee n surface and gravitational energies. Results of this model are in good agr eement with experiments in terms of volume, as well as density and surface energy, dependence of the oscillation frequency.