Modulation instability and capillary wave turbulence
Research School of Physics and Engineering, The Australian National University - Canberra, ACT 0200, Australia
Accepted: 23 June 2010
Formation of turbulence of capillary waves is studied in laboratory experiments. The spectra show multiple exponentially decreasing harmonics of the parametrically excited wave which nonlinearly broaden with the increase in forcing. Spectral broadening leads to the development of the spectral continuum which scales as ∝ f−2.8, in agreement with the weak turbulence theory (WTT). Modulation instability of capillary waves is shown to be responsible for the transition from discrete to broadband spectrum. The instability leads to spectral broadening of the harmonics, randomization of their phases, it isolates the wave field from the wall, eventually allows the transition from 4- to 3-wave interactions as the dominant nonlinear process, thus creating the prerequisites assumed in WTT.
PACS: 47.35.Pq – Capillary waves / 05.45.-a – Nonlinear dynamics and chaos
© EPLA, 2010