The role of Lagrangian drift in the generation of surface waves by wind.
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| Title: | The role of Lagrangian drift in the generation of surface waves by wind. |
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| Authors: | Seitz, L.R.1 (AUTHOR) lulabel_seitz@brown.edu, Freilich, Mara A.1,2 (AUTHOR), Pizzo, Nick3 (AUTHOR) |
| Source: | Journal of Fluid Mechanics. 4/10/2026, Vol. 1032, p1-36. 36p. |
| Subjects: | Wind waves, Wave amplification, Ocean-atmosphere interaction, Surface waves (Fluids), Fluid dynamics, Fluid flow, Stability of nonlinear systems |
| Abstract: | A nonlinear stability analysis entirely in the Lagrangian frame is conducted, revealing the fundamental role of the wave-induced mean flow in modifying further wave growth and providing new insight into the classic problem of wave generation by wind. The prevailing theory, a critical-layer resonance mechanism proposed by Miles (J. Fluid Mech., 1957, vol. 3, no. 2, pp. 185–204), has seen numerous refinements; yet, the role of Lagrangian drift – the velocity a fluid parcel actually experiences – in wave growth was not understood. Our analysis first recovers the classic Miles growth rate from linear theory before extending it to third order in the wave slope to derive a modified growth rate. The leading-order wave-induced mean flow alters the higher-order instability, manifesting as a suppression of growth with increasing wave steepness for the realistic wind profiles considered. This modified growth rate shows good agreement with experimental observations, explaining the observed steepness-dependent suppression via a single physical mechanism. An integral momentum budget clarifies this mechanism, revealing that the wave-induced current alters the coupling between the total phase speed and the total Lagrangian mean flow at the critical level (as defined in the linear theory), thereby acting to reduce the efficiency of momentum transfer. Notably, this Lagrangian drift is precisely what Doppler-shift-based remote sensing of upper ocean currents measure, providing a direct observational pathway to account for this wave-induced feedback in studies of air–sea coupling. More broadly, this approach can be generalised to analyse other shear instabilities and provides a direct path towards refining wind-stress parametrisations. [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: 193224660 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The role of Lagrangian drift in the generation of surface waves by wind. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Seitz%2C+L%2ER%2E%22">Seitz, L.R.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> lulabel_seitz@brown.edu</i><br /><searchLink fieldCode="AR" term="%22Freilich%2C+Mara+A%2E%22">Freilich, Mara A.</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Pizzo%2C+Nick%22">Pizzo, Nick</searchLink><relatesTo>3</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Fluid+Mechanics%22">Journal of Fluid Mechanics</searchLink>. 4/10/2026, Vol. 1032, p1-36. 36p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Wind+waves%22">Wind waves</searchLink><br /><searchLink fieldCode="DE" term="%22Wave+amplification%22">Wave amplification</searchLink><br /><searchLink fieldCode="DE" term="%22Ocean-atmosphere+interaction%22">Ocean-atmosphere interaction</searchLink><br /><searchLink fieldCode="DE" term="%22Surface+waves+%28Fluids%29%22">Surface waves (Fluids)</searchLink><br /><searchLink fieldCode="DE" term="%22Fluid+dynamics%22">Fluid dynamics</searchLink><br /><searchLink fieldCode="DE" term="%22Fluid+flow%22">Fluid flow</searchLink><br /><searchLink fieldCode="DE" term="%22Stability+of+nonlinear+systems%22">Stability of nonlinear systems</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: A nonlinear stability analysis entirely in the Lagrangian frame is conducted, revealing the fundamental role of the wave-induced mean flow in modifying further wave growth and providing new insight into the classic problem of wave generation by wind. The prevailing theory, a critical-layer resonance mechanism proposed by Miles (J. Fluid Mech., 1957, vol. 3, no. 2, pp. 185–204), has seen numerous refinements; yet, the role of Lagrangian drift – the velocity a fluid parcel actually experiences – in wave growth was not understood. Our analysis first recovers the classic Miles growth rate from linear theory before extending it to third order in the wave slope to derive a modified growth rate. The leading-order wave-induced mean flow alters the higher-order instability, manifesting as a suppression of growth with increasing wave steepness for the realistic wind profiles considered. This modified growth rate shows good agreement with experimental observations, explaining the observed steepness-dependent suppression via a single physical mechanism. An integral momentum budget clarifies this mechanism, revealing that the wave-induced current alters the coupling between the total phase speed and the total Lagrangian mean flow at the critical level (as defined in the linear theory), thereby acting to reduce the efficiency of momentum transfer. Notably, this Lagrangian drift is precisely what Doppler-shift-based remote sensing of upper ocean currents measure, providing a direct observational pathway to account for this wave-induced feedback in studies of air–sea coupling. More broadly, this approach can be generalised to analyse other shear instabilities and provides a direct path towards refining wind-stress parametrisations. [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.2026.11348 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 36 StartPage: 1 Subjects: – SubjectFull: Wind waves Type: general – SubjectFull: Wave amplification Type: general – SubjectFull: Ocean-atmosphere interaction Type: general – SubjectFull: Surface waves (Fluids) Type: general – SubjectFull: Fluid dynamics Type: general – SubjectFull: Fluid flow Type: general – SubjectFull: Stability of nonlinear systems Type: general Titles: – TitleFull: The role of Lagrangian drift in the generation of surface waves by wind. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Seitz, L.R. – PersonEntity: Name: NameFull: Freilich, Mara A. – PersonEntity: Name: NameFull: Pizzo, Nick IsPartOfRelationships: – BibEntity: Dates: – D: 10 M: 04 Text: 4/10/2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 00221120 Numbering: – Type: volume Value: 1032 Titles: – TitleFull: Journal of Fluid Mechanics Type: main |
| ResultId | 1 |
