Two-scale wave patterns on a periodically excited miscible liquid-liquid interface

We have discovered a peculiar behaviour of the interface between two miscible liquids placed in a finite-size container under horizontal vibration. We provide evidence that periodic wave patterns created by the Kelvin-Helmholtz instability and Faraday waves simultaneously exist in the same system of miscible liquids. We show experimentally in reduced and normal gravity that large-scale frozen waves yield Faraday waves with a smaller wavelength on a diffusive interface. The emergence of the different scale patterns observed in the experiments is confirmed numerically and explained theoretically.SCOPUS: ar.j