URL: https://journals.aps.org/pre/abstract/10.1103/PhysRevE.107.045101
Abstract:
We report the observation of nonlinear three-wave resonant
interactions between two different branches of the dispersion
relation of hydrodynamic waves, namely the gravity-capillary and
sloshing modes. These atypical interactions are investigated
within a torus of fluid for which the sloshing mode can be
easily excited. A triadic resonance instability is then observed
due to this three-wave two-branch interaction mechanism. An
exponential growth of the instability and phase locking are
evidenced. The efficiency of this interaction is found to be
maximal when the gravity-capillary phase velocity matches the
group velocity of the sloshing mode. For a stronger forcing,
additional waves are generated by a cascade of three-wave
interactions populating the wave spectrum. Such a three-wave
two-branch interaction mechanism is probably not restricted to
hydrodynamics and could be of interest in other systems
involving several propagation modes.