Studying propagating turbulent structures in the near wake of a sphere using Hilbert proper orthogonal decomposition.
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| Title: | Studying propagating turbulent structures in the near wake of a sphere using Hilbert proper orthogonal decomposition. |
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| Authors: | Davey, Shaun1 shaun.davey@monash.edu, Atkinson, Callum1, Soria, Julio1 |
| Source: | Journal of Fluid Mechanics. 3/10/2026, Vol. 1030, p1-41. 41p. |
| Subjects: | Proper orthogonal decomposition, Hilbert transform, Turbulent flow, Coherent structures, Turbulence, Vortex shedding |
| Abstract: | Turbulent flows, despite their apparent randomness, exhibit coherent structures that underpin their dynamics. Proper orthogonal decomposition (POD) has been widely used to extract these structures from experimental data. Periodic features such as vortex shedding can appear as POD mode pairs in strongly periodic flows, but detecting propagating structures in more complex flows is challenging. Hilbert proper orthogonal decomposition (HPOD) addresses this by applying POD to the analytic signal of the turbulent fluctuations, which yields complex modes with a π/2 phase shift between the real and imaginary components. These modes capture propagating structures effectively but introduce spectral leakage from the Hilbert transform used to derive the analytic signal. The current work investigates the relationship between the modes of the POD and those of the HPOD on the velocity fluctuations in the wake of a sphere. By comparing their outputs, POD mode pairs that correspond to the same propagating structures revealed by HPOD are identified. Furthermore, this study explores whether computing the analytic signal of the POD modes can replicate the HPOD modes, offering a more computationally efficient method for determining the pairs of POD modes that represent propagating structures. The results show that the pairs of POD modes identified by the HPOD can be determined more efficiently using the Hilbert transform directly on the POD modes. This method enhances the interpretive power of POD, enabling more detailed analysis of the turbulent dynamics without the need to compute the analytic signal of the entire turbulent fluctuation data. [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: 192858540 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Studying propagating turbulent structures in the near wake of a sphere using Hilbert proper orthogonal decomposition. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Davey%2C+Shaun%22">Davey, Shaun</searchLink><relatesTo>1</relatesTo><i> shaun.davey@monash.edu</i><br /><searchLink fieldCode="AR" term="%22Atkinson%2C+Callum%22">Atkinson, Callum</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Soria%2C+Julio%22">Soria, Julio</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Fluid+Mechanics%22">Journal of Fluid Mechanics</searchLink>. 3/10/2026, Vol. 1030, p1-41. 41p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Proper+orthogonal+decomposition%22">Proper orthogonal decomposition</searchLink><br /><searchLink fieldCode="DE" term="%22Hilbert+transform%22">Hilbert transform</searchLink><br /><searchLink fieldCode="DE" term="%22Turbulent+flow%22">Turbulent flow</searchLink><br /><searchLink fieldCode="DE" term="%22Coherent+structures%22">Coherent structures</searchLink><br /><searchLink fieldCode="DE" term="%22Turbulence%22">Turbulence</searchLink><br /><searchLink fieldCode="DE" term="%22Vortex+shedding%22">Vortex shedding</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Turbulent flows, despite their apparent randomness, exhibit coherent structures that underpin their dynamics. Proper orthogonal decomposition (POD) has been widely used to extract these structures from experimental data. Periodic features such as vortex shedding can appear as POD mode pairs in strongly periodic flows, but detecting propagating structures in more complex flows is challenging. Hilbert proper orthogonal decomposition (HPOD) addresses this by applying POD to the analytic signal of the turbulent fluctuations, which yields complex modes with a π/2 phase shift between the real and imaginary components. These modes capture propagating structures effectively but introduce spectral leakage from the Hilbert transform used to derive the analytic signal. The current work investigates the relationship between the modes of the POD and those of the HPOD on the velocity fluctuations in the wake of a sphere. By comparing their outputs, POD mode pairs that correspond to the same propagating structures revealed by HPOD are identified. Furthermore, this study explores whether computing the analytic signal of the POD modes can replicate the HPOD modes, offering a more computationally efficient method for determining the pairs of POD modes that represent propagating structures. The results show that the pairs of POD modes identified by the HPOD can be determined more efficiently using the Hilbert transform directly on the POD modes. This method enhances the interpretive power of POD, enabling more detailed analysis of the turbulent dynamics without the need to compute the analytic signal of the entire turbulent fluctuation data. [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.2026.11201 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 41 StartPage: 1 Subjects: – SubjectFull: Proper orthogonal decomposition Type: general – SubjectFull: Hilbert transform Type: general – SubjectFull: Turbulent flow Type: general – SubjectFull: Coherent structures Type: general – SubjectFull: Turbulence Type: general – SubjectFull: Vortex shedding Type: general Titles: – TitleFull: Studying propagating turbulent structures in the near wake of a sphere using Hilbert proper orthogonal decomposition. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Davey, Shaun – PersonEntity: Name: NameFull: Atkinson, Callum – PersonEntity: Name: NameFull: Soria, Julio IsPartOfRelationships: – BibEntity: Dates: – D: 10 M: 03 Text: 3/10/2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 00221120 Numbering: – Type: volume Value: 1030 Titles: – TitleFull: Journal of Fluid Mechanics Type: main |
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