Turbulent spectrum of 2D internal gravity waves

Fuente: arXiv
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Hauptverfasser: Shavit, Michal, Bühler, Oliver, Shatah, Jalal
Format: Preprint
Veröffentlicht: 2024
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author Shavit, Michal
Bühler, Oliver
Shatah, Jalal
author_facet Shavit, Michal
Bühler, Oliver
Shatah, Jalal
contents We find the turbulent energy spectrum of weakly interacting 2D internal gravity waves using the full, non-hydrostatic dispersion relation. This spectrum is an exact solution of a regularized kinetic equation, from which the zero-frequency shear modes have been excised by a careful limiting process. This is a new method in wave kinetic theory. The turbulent spectrum agrees with the 2D oceanic Garrett--Munk spectrum for frequencies large compared to the Coriolis frequency and vertical scales small compared to the depth of the ocean. We show that this turbulent spectrum is the unique power law solution to the steady kinetic equation with a non-zero radial flux. Our solution provides an interesting insight into a turbulent energy cascade in an anisotropic system -- like isotropic turbulence it is self-similar in scale, but its angular part is peaked along the curve of vanishing frequency and is self-similar in frequency.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06010
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Turbulent spectrum of 2D internal gravity waves
Shavit, Michal
Bühler, Oliver
Shatah, Jalal
Fluid Dynamics
Atmospheric and Oceanic Physics
Geophysics
We find the turbulent energy spectrum of weakly interacting 2D internal gravity waves using the full, non-hydrostatic dispersion relation. This spectrum is an exact solution of a regularized kinetic equation, from which the zero-frequency shear modes have been excised by a careful limiting process. This is a new method in wave kinetic theory. The turbulent spectrum agrees with the 2D oceanic Garrett--Munk spectrum for frequencies large compared to the Coriolis frequency and vertical scales small compared to the depth of the ocean. We show that this turbulent spectrum is the unique power law solution to the steady kinetic equation with a non-zero radial flux. Our solution provides an interesting insight into a turbulent energy cascade in an anisotropic system -- like isotropic turbulence it is self-similar in scale, but its angular part is peaked along the curve of vanishing frequency and is self-similar in frequency.
title Turbulent spectrum of 2D internal gravity waves
topic Fluid Dynamics
Atmospheric and Oceanic Physics
Geophysics
url https://arxiv.org/abs/2406.06010