Transition from Weak Wave Turbulence to Soliton-Gas

TL;DR

This study experimentally explores how finite water depth influences wave turbulence, revealing a transition from weak turbulence to a soliton-gas regime characterized by changes in energy transfer and spectral properties.

Contribution

It provides the first detailed experimental analysis of the transition from wave turbulence to soliton-gas regimes as water depth and forcing are varied.

Findings

Transition from weak turbulence to soliton-gas observed with decreasing depth.

Energy transfer efficiency decreases as dispersion is reduced.

Fourier spectra characterize the transition between regimes.

Abstract

We report an experimental investigation of the effect of finite depth on the statistical properties of wave turbulence at the surface of water in the gravity-capillary range. We tune the wave dispersion and the level of nonlinearity by modifying the depth of water and the forcing respectively. We use space-time resolved profilometry to reconstruct the deformed surface of water. When decreasing the water depth, we observe a drastic transition between weak turbulence at the weakest forcing and a solitonic regime at stronger forcing. We characterize the transition between both states by studying their Fourier Spectra. We also study the efficiency of energy transfer in the weak turbulence regime. We report a loss of efficiency of angular transfer as the dispersion of the wave is reduced until the system bifurcates into the solitonic regime.