Michael R. Cox
Inertia-gravity-wave diffusion by geostrophic turbulence: the impact of flow time dependence
Cox, Michael R.; Kafiabad, Hossein A.; Vanneste, Jacques
Authors
Abstract
The scattering of three-dimensional inertia-gravity waves by a turbulent geostrophic flow leads to the redistribution of their action through what is approximately a diffusion process in wavevector space. The corresponding diffusivity tensor was obtained by Kafiabad et al. (J. Fluid Mech., vol. 869, 2019, R7) under the assumption of a time-independent geostrophic flow. We relax this assumption to examine how the weak diffusion of wave action across constant-frequency cones that results from the slow time dependence of the geostrophic flow affects the distribution of wave energy. We find that the stationary wave-energy spectrum that arises from a single-frequency wave forcing is localised within a thin boundary layer around the constant-frequency cone, with a thickness controlled by the acceleration spectrum of the geostrophic flow. We obtain an explicit analytic formula for the wave-energy spectrum which shows good agreement with the results of a high-resolution simulation of the Boussinesq equations.
Citation
Cox, M. R., Kafiabad, H. A., & Vanneste, J. (2023). Inertia-gravity-wave diffusion by geostrophic turbulence: the impact of flow time dependence. Journal of Fluid Mechanics, 958, Article A21. https://doi.org/10.1017/jfm.2023.83
Journal Article Type | Article |
---|---|
Online Publication Date | Mar 3, 2023 |
Publication Date | 2023 |
Deposit Date | Mar 12, 2023 |
Publicly Available Date | Apr 24, 2023 |
Journal | Journal of Fluid Mechanics |
Print ISSN | 0022-1120 |
Electronic ISSN | 1469-7645 |
Publisher | Cambridge University Press |
Peer Reviewed | Peer Reviewed |
Volume | 958 |
Article Number | A21 |
DOI | https://doi.org/10.1017/jfm.2023.83 |
Public URL | https://durham-repository.worktribe.com/output/1178545 |
Related Public URLs | https://arxiv.org/abs/2207.09386 |
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Copyright Statement
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
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