Dynamics of Two-liquid System at Rotation and Vibration with Equal Frequencies

Abstract

The impact of vibrations on the dynamics of a system of two immiscible liquids filling a rotating container is studied experimentally. A horizontal cylindrical container is rotating at a rate sufficient for the liquids, whose densities are not equal, to become steadily distributed in the form of core and annulus. The vibrational motion of the container has a frequency virtually equal to that of rotation. It is demonstrated that at the coincidence of the frequencies the container’s oscillations lead to the transformation of the centrifugal field. As a result, the column of light liquid is shifted steadily in the rotating frame of reference. With the increase in the amplitude of vibrational forcing, in a threshold manner the liquid–liquid interface loses its axial symmetry, and a centrifugal wave emerges on it. The threshold of wave onset is determined by the dimensionless vibrational acceleration. The obtained results demonstrate a possibility to apply vibrations for the positioning of a liquid core in a rotating container and for the control of its dynamics.