A new article by Costanza Rodda et al. describing an experimental study on internal gravity wave turbulence has just been published in Physical Review Fluids . The title is: Experimental observations of internal wave turbulence transition in a stratified fluid . Such experiments in the Coriolis platform are complicated and involve a lot of people: Costanza Rodda, Clément Savaro, Géraldine Davis, Jason Reneuve, Pierre Augier, Joël Sommeria, Thomas Valran, Samuel Viboud, and Nicolas Mordant.
Abstract: Recent developments of the weak turbulence theory applied to internal waves exhibit a power-law solution of the kinetic energy equation close to the oceanic Garrett-Munk spectrum, confirming weakly nonlinear wave interactions as a likely explanation of the observed oceanic spectra. However, finite-size effects can hinder wave interactions in bounded domains, and observations often differ from theoretical predictions. This paper studies the dynamical regimes experimentally developing in a stratified fluid forced by internal gravity waves in a pentagonal domain. We find that by changing the shape and increasing the dimensions of the domain finite-size effects diminish and wave turbulence is observed. In this regime, the temporal spectra decay with a slope compatible with the Garrett-Munk spectra. Different regimes appear by changing the forcing conditions, namely, discrete wave turbulence, weak wave turbulence, and strongly stratified turbulence. The buoyancy Reynolds number \(Re_b\) marks well the transitions between the regimes, with weak wave turbulence occurring for \(1 \leq Re_b \leq 3.5\) and strongly nonlinear stratified turbulence for higher \(Re_b\) .