Dynamics of two liquids in a non-uniformly rotating horizontal cylinder

Controlling the shape of interfacial boundary is an important technological task. The effect rotation velocity modulation on interface between light viscous and denser low viscosity fluid in a rotating horizontal cylinder studied experimentally. Liquids are characterized by high contrast viscosities, these glycerin low-viscosity (denser) fluorinert FC-40. Glycerin stained with rhodamine, which makes it possible to study photo registration accuracy when illuminating liquids green laser, causes rhodamine fluorescence. Experiments carried out centrifuged state gravity field has no while varying speed, as well amplitude frequency librations. It found that librations qualitatively change near ends cavity without affecting cylindrical middle part. shown this due different "viscous" interactions oscillating cavity, result performs radial oscillations librations, latter leads averaged displacement wetting ends, increases amplitude. At certain amplitudes, contact line reaches outer cavity. dynamic equilibrium densities determined interaction ends.