Non stationary wave turbulence in an elastic plate

TL;DR

This study investigates how wave turbulence in an elastic plate decays after stopping external forcing, showing that decay leads to isotropy and spectra aligning better with weak turbulence theory, highlighting the impact of forcing and system size.

Contribution

It provides experimental insights into the decay process of wave turbulence in elastic plates and clarifies the effects of forcing and finite system size on turbulence spectra.

Findings

Decay is self-similar and isotropic after forcing stops.

Decaying spectra agree better with weak turbulence theory.

Finite size effects influence the observed turbulence spectra.

Abstract

We report experimental results on the decay of wave turbulence in an elastic plate obtained by stopping the forcing from a stationary turbulent state. In the stationary case, the forcing is seen to induce some anisotropy and a spectrum in disagreement with the weak turbulence theory. After stopping the forcing, almost perfect isotropy is restored. The decay of energy is self similar and the observed decaying spectrum is in better agreement with the prediction of the weak turbulence theory. The dissipative part of the spectrum is partially consistent with the theoretical prediction based on previous work by Kolmakov. This suggest that the non agreement with the weak turbulence theory is mostly due to a spurious effect of the forcing related to the finite size of the system.