Saturation of the Inverse Cascade in Surface Gravity-Wave
Turbulence
E. Falcon1, G. Michel2, G.
Prabhudesai3, A. Cazaubiel1, M. Berhanu1,
N. Mordant4, S. Aumaître5,
and F. Bonnefoy6
1Université de Paris, Univ Paris
Diderot, MSC, UMR 7057 CNRS, F-75 013 Paris, France
2Sorbonne Université, IJLRA, UMR 7190 CNRS, F-75 005
Paris, France
3Ecole Normale Supérieure, LPS, UMR 8550 CNRS, F-75 205
Paris, France
4Université Grenoble Alpes, LEGI, UMR 5519 CNRS, F-38
000 Grenoble, France
5CEA-Saclay, Sphynx, DSM, URA 2464 CNRS, F-91 191
Gif-sur-Yvette, France
6Ecole Centrale de Nantes, LHEEA, UMR 6598 CNRS, F-44
321 Nantes, France
Reference: Physical Review Letters 125,
134501 (2020)
Abstract: We report on the
observation of surface gravity-wave turbulence at scales larger
than the forcing ones in a large basin. In addition to the
downscale transfer usually reported in gravity-wave turbulence,
an upscale transfer is observed, interpreted as the inverse
cascade of weak turbulence theory. A steady state is achieved
when the inverse cascade reaches a scale in between the forcing
wavelength and the basin size, but far from the latter. This
inverse cascade saturation, which depends on the wave steepness,
is probably due to the emergence of nonlinear dissipative
structures such as sharp-crested waves.
Movies:
BassinMEDcutLow.mpeg (35s -
24Mo): Movie of the large-scale wave basin seen from
the shore showing the wave makers, the wall at the opposite
end, the probe array, and the control room. Weak random
forcing conditions.
WeakForcingIMG_7799.mp4
(15s - 17Mo): Movie of the wave field seen from the
shore. Weak random forcing conditions: Wave steepness 0.063
and narrow spectral bandwidth (1.8±0.2 Hz).
HigherForcingIMG_7800.mp4 (15s -
16Mo): Movie of the wave field seen from the shore.
Higher random forcing conditions: Wave steepness 0.98 and
narrow spectral bandwidth (1.8±0.2 Hz).