Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend
This study seeks to characterise the stability of a two-dimensional channel flow involving a 180-degree sharp bend, to infinitesimal three-dimensional disturbances by way of linear stability analysis. A highly accurate global linear stability analysis of the flow is presented via the Reynolds number...
| Main Authors: | , , , |
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| Format: | Proceeding Paper |
| Language: | English |
| Published: |
Australian Fluid Mechanics Society
2014
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/71546/ http://irep.iium.edu.my/71546/7/71546%20Three-dimensional%20Linear%20Stability.pdf |
| _version_ | 1848787467847598080 |
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| author | Mohammed Sapardi, Mohd Azan Hussam, W. K. Potherat, A. Sheard, G. J. |
| author_facet | Mohammed Sapardi, Mohd Azan Hussam, W. K. Potherat, A. Sheard, G. J. |
| author_sort | Mohammed Sapardi, Mohd Azan |
| building | IIUM Repository |
| collection | Online Access |
| description | This study seeks to characterise the stability of a two-dimensional channel flow involving a 180-degree sharp bend, to infinitesimal three-dimensional disturbances by way of linear stability analysis. A highly accurate global linear stability analysis of the flow is presented via the Reynolds number Re varies in the range 100 ≤ Re ≤ 700, this Re range produces steady state two-dimensional flow solutions for bend opening ratio (ratio of bend width on inlet height) β = 1. The two-dimensional base flow solutions demonstrate that as β decreases, the transition from steady to unsteady occurs at lower Reynolds number.
The stability analysis shows that the flow first becomes unstable to a synchronous three-dimensional instability mode with spanwise wavenumber k = 2 at approximately Re = 400, whereas the two-dimensional solution branch undergoes transition to unsteady flow somewhere near Re ≈ 800. Instability mode structures associated with the leading eigenvalues are localized at the re-attachment point of the first separation bubble and the separation point of the second separation bubble. The stability analysis is used to produce neutral stability curves and visualisations of the global modes of the system for typical Reynolds number are also presented. |
| first_indexed | 2025-11-14T17:25:24Z |
| format | Proceeding Paper |
| id | iium-71546 |
| institution | International Islamic University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T17:25:24Z |
| publishDate | 2014 |
| publisher | Australian Fluid Mechanics Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | iium-715462020-07-13T03:31:38Z http://irep.iium.edu.my/71546/ Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend Mohammed Sapardi, Mohd Azan Hussam, W. K. Potherat, A. Sheard, G. J. TJ Mechanical engineering and machinery This study seeks to characterise the stability of a two-dimensional channel flow involving a 180-degree sharp bend, to infinitesimal three-dimensional disturbances by way of linear stability analysis. A highly accurate global linear stability analysis of the flow is presented via the Reynolds number Re varies in the range 100 ≤ Re ≤ 700, this Re range produces steady state two-dimensional flow solutions for bend opening ratio (ratio of bend width on inlet height) β = 1. The two-dimensional base flow solutions demonstrate that as β decreases, the transition from steady to unsteady occurs at lower Reynolds number. The stability analysis shows that the flow first becomes unstable to a synchronous three-dimensional instability mode with spanwise wavenumber k = 2 at approximately Re = 400, whereas the two-dimensional solution branch undergoes transition to unsteady flow somewhere near Re ≈ 800. Instability mode structures associated with the leading eigenvalues are localized at the re-attachment point of the first separation bubble and the separation point of the second separation bubble. The stability analysis is used to produce neutral stability curves and visualisations of the global modes of the system for typical Reynolds number are also presented. Australian Fluid Mechanics Society 2014 Proceeding Paper PeerReviewed application/pdf en http://irep.iium.edu.my/71546/7/71546%20Three-dimensional%20Linear%20Stability.pdf Mohammed Sapardi, Mohd Azan and Hussam, W. K. and Potherat, A. and Sheard, G. J. (2014) Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend. In: 19th Australasian Fluid Mechanics Conference, 8 - 11 Dec 2014, Melbourne, Australia. https://people.eng.unimelb.edu.au/imarusic/proceedings/19/222.pdf |
| spellingShingle | TJ Mechanical engineering and machinery Mohammed Sapardi, Mohd Azan Hussam, W. K. Potherat, A. Sheard, G. J. Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend |
| title | Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend |
| title_full | Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend |
| title_fullStr | Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend |
| title_full_unstemmed | Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend |
| title_short | Three-dimensional linear stability analysis of the flow around a sharp 180-degree bend |
| title_sort | three-dimensional linear stability analysis of the flow around a sharp 180-degree bend |
| topic | TJ Mechanical engineering and machinery |
| url | http://irep.iium.edu.my/71546/ http://irep.iium.edu.my/71546/ http://irep.iium.edu.my/71546/7/71546%20Three-dimensional%20Linear%20Stability.pdf |