The importance of lateral boundary layer drag forces in rotating fluids.
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| Title: | The importance of lateral boundary layer drag forces in rotating fluids. |
|---|---|
| Authors: | Scolan, H.1 (AUTHOR), Williams, P. D.2 (AUTHOR), Verzicco, R.3 (AUTHOR), Flór, J. B.1 (AUTHOR) Jan-Bert.Flor@cnrs.fr |
| Source: | Geophysical & Astrophysical Fluid Dynamics. Feb2026, Vol. 120 Issue 1, p45-70. 26p. |
| Subjects: | Rotating fluid, Fluid friction, Fluid dynamics, Momentum transfer |
| Abstract: | The relative motion of fluids in rotating tanks is opposed by viscous boundary layers at the lateral and horizontal boundaries. The influence of drag at the lateral boundaries is often tacitly assumed to be much weaker than at the horizontal boundaries, allowing the former to be neglected in analytical and numerical models. In the present study, the rationale behind this assumption is scrutinised, analytically, numerically and experimentally. A simple equilibrium torque balance model applied to the one-layer and two-layer configurations of the rotating annulus, predicts that the drag torques at the lateral and horizontal boundaries may be comparable in magnitude (Williams et al., Stochastic resonance in a nonlinear model of a rotating, stratified shear flow, with a simple stochastic inertia-gravity wave parameterization. Nonlinear Process. Geophys. 2004a, 11, 127–135). The effect of lateral boundaries depends on geometrical aspect ratio, radii ratio and Ekman number and can be expected large for experimental configurations with high aspect ratios and low rotation giving larger Ekman number. In this torque model, the thickness of the Stewartson layer can be defined using either a horizontal or a vertical length scale, yielding two distinct models. The strong agreement between the numerical results and the model based on the horizontal length scale, implying an Ekman number based on the width of the container, contrasts with the poor agreement observed for the vertically based model. This discrepancy highlights the importance of lateral boundaries in the momentum balance. Experimental results obtained in the laboratory using both a one-layer cylinder configuration and a two-layer salt-stratified rotating annulus show results that are consistent with the model predictions only if lateral boundary layer drag is included, confirming that lateral boundary layers contribute critically to the equilibrium torque balance. The effect was found weaker in the one-layer configuration than in the two-layer annulus configuration. Insight is also gained from the annulus experiments into the vertical transfer of horizontal momentum across density interfaces, which is of great relevance to geophysical flows. The results are relevant for rotating laboratory experiments. [ABSTRACT FROM AUTHOR] |
| Copyright of Geophysical & Astrophysical Fluid Dynamics is the property of Taylor & Francis Ltd 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: 193526448 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The importance of lateral boundary layer drag forces in rotating fluids. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Scolan%2C+H%2E%22">Scolan, H.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Williams%2C+P%2E+D%2E%22">Williams, P. D.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Verzicco%2C+R%2E%22">Verzicco, R.</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Flór%2C+J%2E+B%2E%22">Flór, J. B.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> Jan-Bert.Flor@cnrs.fr</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Geophysical+%26+Astrophysical+Fluid+Dynamics%22">Geophysical & Astrophysical Fluid Dynamics</searchLink>. Feb2026, Vol. 120 Issue 1, p45-70. 26p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Rotating+fluid%22">Rotating fluid</searchLink><br /><searchLink fieldCode="DE" term="%22Fluid+friction%22">Fluid friction</searchLink><br /><searchLink fieldCode="DE" term="%22Fluid+dynamics%22">Fluid dynamics</searchLink><br /><searchLink fieldCode="DE" term="%22Momentum+transfer%22">Momentum transfer</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The relative motion of fluids in rotating tanks is opposed by viscous boundary layers at the lateral and horizontal boundaries. The influence of drag at the lateral boundaries is often tacitly assumed to be much weaker than at the horizontal boundaries, allowing the former to be neglected in analytical and numerical models. In the present study, the rationale behind this assumption is scrutinised, analytically, numerically and experimentally. A simple equilibrium torque balance model applied to the one-layer and two-layer configurations of the rotating annulus, predicts that the drag torques at the lateral and horizontal boundaries may be comparable in magnitude (Williams et al., Stochastic resonance in a nonlinear model of a rotating, stratified shear flow, with a simple stochastic inertia-gravity wave parameterization. Nonlinear Process. Geophys. 2004a, 11, 127–135). The effect of lateral boundaries depends on geometrical aspect ratio, radii ratio and Ekman number and can be expected large for experimental configurations with high aspect ratios and low rotation giving larger Ekman number. In this torque model, the thickness of the Stewartson layer can be defined using either a horizontal or a vertical length scale, yielding two distinct models. The strong agreement between the numerical results and the model based on the horizontal length scale, implying an Ekman number based on the width of the container, contrasts with the poor agreement observed for the vertically based model. This discrepancy highlights the importance of lateral boundaries in the momentum balance. Experimental results obtained in the laboratory using both a one-layer cylinder configuration and a two-layer salt-stratified rotating annulus show results that are consistent with the model predictions only if lateral boundary layer drag is included, confirming that lateral boundary layers contribute critically to the equilibrium torque balance. The effect was found weaker in the one-layer configuration than in the two-layer annulus configuration. Insight is also gained from the annulus experiments into the vertical transfer of horizontal momentum across density interfaces, which is of great relevance to geophysical flows. The results are relevant for rotating laboratory experiments. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Geophysical & Astrophysical Fluid Dynamics is the property of Taylor & Francis Ltd 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: 10.1080/03091929.2026.2655597 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 26 StartPage: 45 Subjects: – SubjectFull: Rotating fluid Type: general – SubjectFull: Fluid friction Type: general – SubjectFull: Fluid dynamics Type: general – SubjectFull: Momentum transfer Type: general Titles: – TitleFull: The importance of lateral boundary layer drag forces in rotating fluids. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Scolan, H. – PersonEntity: Name: NameFull: Williams, P. D. – PersonEntity: Name: NameFull: Verzicco, R. – PersonEntity: Name: NameFull: Flór, J. B. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 02 Text: Feb2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 03091929 Numbering: – Type: volume Value: 120 – Type: issue Value: 1 Titles: – TitleFull: Geophysical & Astrophysical Fluid Dynamics Type: main |
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