Weak and strong wave turbulence spectra for elastic thin plate.

A variety of statistically steady energy spectra in elastic wave turbulence have been reported in numerical simulations, experiments, and theoretical studies. Focusing on the energy levels of the system, we perform direct numerical simulations according to the Föppl-von Kármán equation, and successfully reproduce the variability of the energy spectra by changing the magnitude of external force systematically. When the total energies in wave fields are small, the energy spectra are close to a statistically steady solution of the kinetic equation in the weak turbulence theory. On the other hand, in large-energy wave fields, another self-similar spectrum is found. The coexistence of the weakly nonlinear spectrum in large wave numbers and the strongly nonlinear spectrum in small wave numbers is also found in moderate energy wave fields.