Experimental study of the nonlinear saturation of the elliptical instability: inertial wave turbulence versus geostrophic turbulence.
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| Title: | Experimental study of the nonlinear saturation of the elliptical instability: inertial wave turbulence versus geostrophic turbulence. |
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| Authors: | Le Reun, Thomas1 (AUTHOR) lereun@irphe.univ-mrs.fr, Favier, Benjamin1 (AUTHOR), Le Bars, Michael1 (AUTHOR) |
| Source: | Journal of Fluid Mechanics. 11/25/2019, Vol. 879, p296-326. 31p. |
| Subjects: | Rotating fluid, Waves (Fluid mechanics), Turbulence, Rotational motion, Exponential functions |
| Abstract: | In this paper, we present an experimental investigation of the turbulent saturation of the flow driven by the parametric resonance of inertial waves in a rotating fluid. In our set-up, a half-metre wide ellipsoid filled with water is brought to solid-body rotation, and then undergoes sustained harmonic modulation of its rotation rate. This triggers the exponential growth of a pair of inertial waves via a mechanism called the libration-driven elliptical instability. Once the saturation of this instability is reached, we observe a turbulent state for which energy is injected into the resonant inertial waves only. Depending on the amplitude of the rotation rate modulation, two different saturation states are observed. At large forcing amplitudes, the saturation flow mainly consists of a steady, geostrophic anticyclone. Its amplitude vanishes as the forcing amplitude is decreased while remaining above the threshold of the elliptical instability. Below this secondary transition, the saturation flow is a superposition of inertial waves which are in weakly nonlinear resonant interaction, a state that could asymptotically lead to inertial wave turbulence. In addition to being a first experimental observation of a wave-dominated saturation in unstable rotating flows, the present study is also an experimental confirmation of the model of Le Reun et al. (Phys. Rev. Lett. , vol. 119 (3), 2017, 034502) who introduced the possibility of these two turbulent regimes. The transition between these two regimes and their relevance to geophysical applications are finally discussed. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Fluid Mechanics is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 139160380 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Experimental study of the nonlinear saturation of the elliptical instability: inertial wave turbulence versus geostrophic turbulence. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Le+Reun%2C+Thomas%22">Le Reun, Thomas</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> lereun@irphe.univ-mrs.fr</i><br /><searchLink fieldCode="AR" term="%22Favier%2C+Benjamin%22">Favier, Benjamin</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Le+Bars%2C+Michael%22">Le Bars, Michael</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Fluid+Mechanics%22">Journal of Fluid Mechanics</searchLink>. 11/25/2019, Vol. 879, p296-326. 31p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Rotating+fluid%22">Rotating fluid</searchLink><br /><searchLink fieldCode="DE" term="%22Waves+%28Fluid+mechanics%29%22">Waves (Fluid mechanics)</searchLink><br /><searchLink fieldCode="DE" term="%22Turbulence%22">Turbulence</searchLink><br /><searchLink fieldCode="DE" term="%22Rotational+motion%22">Rotational motion</searchLink><br /><searchLink fieldCode="DE" term="%22Exponential+functions%22">Exponential functions</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: In this paper, we present an experimental investigation of the turbulent saturation of the flow driven by the parametric resonance of inertial waves in a rotating fluid. In our set-up, a half-metre wide ellipsoid filled with water is brought to solid-body rotation, and then undergoes sustained harmonic modulation of its rotation rate. This triggers the exponential growth of a pair of inertial waves via a mechanism called the libration-driven elliptical instability. Once the saturation of this instability is reached, we observe a turbulent state for which energy is injected into the resonant inertial waves only. Depending on the amplitude of the rotation rate modulation, two different saturation states are observed. At large forcing amplitudes, the saturation flow mainly consists of a steady, geostrophic anticyclone. Its amplitude vanishes as the forcing amplitude is decreased while remaining above the threshold of the elliptical instability. Below this secondary transition, the saturation flow is a superposition of inertial waves which are in weakly nonlinear resonant interaction, a state that could asymptotically lead to inertial wave turbulence. In addition to being a first experimental observation of a wave-dominated saturation in unstable rotating flows, the present study is also an experimental confirmation of the model of Le Reun et al. (Phys. Rev. Lett. , vol. 119 (3), 2017, 034502) who introduced the possibility of these two turbulent regimes. The transition between these two regimes and their relevance to geophysical applications are finally discussed. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Fluid Mechanics is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1017/jfm.2019.646 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 31 StartPage: 296 Subjects: – SubjectFull: Rotating fluid Type: general – SubjectFull: Waves (Fluid mechanics) Type: general – SubjectFull: Turbulence Type: general – SubjectFull: Rotational motion Type: general – SubjectFull: Exponential functions Type: general Titles: – TitleFull: Experimental study of the nonlinear saturation of the elliptical instability: inertial wave turbulence versus geostrophic turbulence. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Le Reun, Thomas – PersonEntity: Name: NameFull: Favier, Benjamin – PersonEntity: Name: NameFull: Le Bars, Michael IsPartOfRelationships: – BibEntity: Dates: – D: 25 M: 11 Text: 11/25/2019 Type: published Y: 2019 Identifiers: – Type: issn-print Value: 00221120 Numbering: – Type: volume Value: 879 Titles: – TitleFull: Journal of Fluid Mechanics Type: main |
| ResultId | 1 |
