The destabilisation of shear layers by asymmetric confinement and stratification.
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| Title: | The destabilisation of shear layers by asymmetric confinement and stratification. |
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| Authors: | Turner, Matthew R.1 m.turner@surrey.ac.uk |
| Source: | Journal of Fluid Mechanics. 6/10/2026, Vol. 1036, p1-37. 46p. |
| Subjects: | Shear flow, Flow instability, Fluid dynamics |
| Abstract: | The absolute and convective instability properties of a parallel shear flow in a stratified fluid, confined between two parallel rigid plates is considered. The flow is assumed to be two-dimensional, inviscid and incompressible, and is modelled using both a discontinuous two-layer stratification profile and a continuous stratification profile. Significantly, it is found that asymmetrically confining the flow by the two plates, and asymmetrically positioning the density interface such that it does not occur at the centre of the shear layer, both lead to a destabilisation of the flow for a range of flow parameter values, with an absolute instability occurring for an increased parameter range. We identify parameter regimes for asymmetric confinement where the destabilising effect is strong enough to generate an absolutely unstable co-flow shear layer; this contrasts with the unconfined case for which only absolutely unstable counterflow shear layers exist. In the semi-confined case (i.e. asymmetric confinement by one plate) it is found that the most unstable scenario occurs when the plate is placed in the faster/lighter stream. The robustness of the results found for a discontinuous density interface are confirmed using a continuous density profile. These results give valuable new insight into a class of flows such as coaxial injectors for high-speed fluid atomisation. [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: 194752299 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The destabilisation of shear layers by asymmetric confinement and stratification. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Turner%2C+Matthew+R%2E%22">Turner, Matthew R.</searchLink><relatesTo>1</relatesTo><i> m.turner@surrey.ac.uk</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Fluid+Mechanics%22">Journal of Fluid Mechanics</searchLink>. 6/10/2026, Vol. 1036, p1-37. 46p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Shear+flow%22">Shear flow</searchLink><br /><searchLink fieldCode="DE" term="%22Flow+instability%22">Flow instability</searchLink><br /><searchLink fieldCode="DE" term="%22Fluid+dynamics%22">Fluid dynamics</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The absolute and convective instability properties of a parallel shear flow in a stratified fluid, confined between two parallel rigid plates is considered. The flow is assumed to be two-dimensional, inviscid and incompressible, and is modelled using both a discontinuous two-layer stratification profile and a continuous stratification profile. Significantly, it is found that asymmetrically confining the flow by the two plates, and asymmetrically positioning the density interface such that it does not occur at the centre of the shear layer, both lead to a destabilisation of the flow for a range of flow parameter values, with an absolute instability occurring for an increased parameter range. We identify parameter regimes for asymmetric confinement where the destabilising effect is strong enough to generate an absolutely unstable co-flow shear layer; this contrasts with the unconfined case for which only absolutely unstable counterflow shear layers exist. In the semi-confined case (i.e. asymmetric confinement by one plate) it is found that the most unstable scenario occurs when the plate is placed in the faster/lighter stream. The robustness of the results found for a discontinuous density interface are confirmed using a continuous density profile. These results give valuable new insight into a class of flows such as coaxial injectors for high-speed fluid atomisation. [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.2026.11648 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 46 StartPage: 1 Subjects: – SubjectFull: Shear flow Type: general – SubjectFull: Flow instability Type: general – SubjectFull: Fluid dynamics Type: general Titles: – TitleFull: The destabilisation of shear layers by asymmetric confinement and stratification. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Turner, Matthew R. IsPartOfRelationships: – BibEntity: Dates: – D: 10 M: 06 Text: 6/10/2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 00221120 Numbering: – Type: volume Value: 1036 Titles: – TitleFull: Journal of Fluid Mechanics Type: main |
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