Vibrational instabilities at the interface separating two immiscible liquids in microgravity

Resumen

A wide variety of interfacial phenomena occurs in vibrated fluid systems, depending on frequency, amplitude and forcing orientation. On earth, there is a clear qualitative difference between vertical and horizontal vibrations. Vertical vibrations can be understood as a modulation of effective gravity and may be stabilizing, as with the Rayleigh-Taylor instability (Wolf 1970), or destabilizing, as with the phenomenon of Faraday waves (Faraday 1831). Horizontal forcing, on the other hand, immediately excites harmonic waves near the container boundaries. When a critical amplitude is reached, it also excites subharmonic cross-waves (Garret, 1970). If the interface separates immiscible layers of different viscosity, vibrations can lead to frozen waves (Lyubimov, Cherepanov 1986; Talib et al. 2007), which are generally bounded by the restoring effects of gravity and interfacial tension.