The motion of a liquid droplet in a liquid with density different from
that of the liquid composing the droplet and subjected to harmonic ex
citations is investigated. Nonlinear equations are obtained that descr
ibe the translational motion of the droplet and its oscillations. It i
s shown by numerical means that, under the essential resonance conditi
ons, the droplet ascends by a cascade method if the value of the load
coefficient is small.