Adaptive drag reduction of a sphere using smart morphable skin
In this study, a novel smart surface-morphing technique is devised that dynamically optimises roughness parameter on a sphere with varying flow conditions to minimise drag. A comprehensive series of experiments are first performed to systematically study the effect of dimple depth ratios in the rang...
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| Language: | English |
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Cambridge University Press
2025-01-01
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| Series: | Flow |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S2633425925000078/type/journal_article |
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| author | Rodrigo Vilumbrales-Garcia Putu Brahmanda Sudarsana Anchal Sareen |
| author_facet | Rodrigo Vilumbrales-Garcia Putu Brahmanda Sudarsana Anchal Sareen |
| author_sort | Rodrigo Vilumbrales-Garcia |
| collection | DOAJ |
| description | In this study, a novel smart surface-morphing technique is devised that dynamically optimises roughness parameter on a sphere with varying flow conditions to minimise drag. A comprehensive series of experiments are first performed to systematically study the effect of dimple depth ratios in the range of 0 ≤ k/d ≤ 2 × 10−2 across a Reynolds number range of 6 × 104 ≤ Re ≤ 1.3 × 105. It is observed that k/d significantly affects both the onset of the drag crisis and the minimum achievable drag. For a constant Re, drag monotonically reduces as k/d increases. However, there is a critical threshold beyond which drag starts to increase. Particle image velocimetry (PIV) reveals a delay in flow separation on the sphere’s surface with increasing k/d, causing the flow separation angle to shift downstream. This results in a smaller wake size and reduced drag. However, when k/d exceeds the critical threshold, flow separation moves upstream, causing an increase in drag. Using the experimental data, a predictive model is developed relating optimal k/d to Re for minimising drag. This control model is then implemented to demonstrate closed-loop drag control of a sphere. The results demonstrate up to a 50 % reduction in drag compared with a smooth sphere, across all Reynolds numbers tested. |
| format | Article |
| id | doaj-art-93946ff732d74edba2ac01ea97db1849 |
| institution | DOAJ |
| issn | 2633-4259 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Flow |
| spelling | doaj-art-93946ff732d74edba2ac01ea97db18492025-08-20T03:10:32ZengCambridge University PressFlow2633-42592025-01-01510.1017/flo.2025.7Adaptive drag reduction of a sphere using smart morphable skinRodrigo Vilumbrales-Garcia0https://orcid.org/0000-0003-3778-0082Putu Brahmanda Sudarsana1Anchal Sareen2https://orcid.org/0000-0002-5384-2071Department of Naval Architecture and Marine Engineering, University of Michigan, Ann Arbor, MI, USADepartment of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USADepartment of Naval Architecture and Marine Engineering, University of Michigan, Ann Arbor, MI, USA Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USAIn this study, a novel smart surface-morphing technique is devised that dynamically optimises roughness parameter on a sphere with varying flow conditions to minimise drag. A comprehensive series of experiments are first performed to systematically study the effect of dimple depth ratios in the range of 0 ≤ k/d ≤ 2 × 10−2 across a Reynolds number range of 6 × 104 ≤ Re ≤ 1.3 × 105. It is observed that k/d significantly affects both the onset of the drag crisis and the minimum achievable drag. For a constant Re, drag monotonically reduces as k/d increases. However, there is a critical threshold beyond which drag starts to increase. Particle image velocimetry (PIV) reveals a delay in flow separation on the sphere’s surface with increasing k/d, causing the flow separation angle to shift downstream. This results in a smaller wake size and reduced drag. However, when k/d exceeds the critical threshold, flow separation moves upstream, causing an increase in drag. Using the experimental data, a predictive model is developed relating optimal k/d to Re for minimising drag. This control model is then implemented to demonstrate closed-loop drag control of a sphere. The results demonstrate up to a 50 % reduction in drag compared with a smooth sphere, across all Reynolds numbers tested.https://www.cambridge.org/core/product/identifier/S2633425925000078/type/journal_articlebluff bodydrag reductionflow controlwake control |
| spellingShingle | Rodrigo Vilumbrales-Garcia Putu Brahmanda Sudarsana Anchal Sareen Adaptive drag reduction of a sphere using smart morphable skin Flow bluff body drag reduction flow control wake control |
| title | Adaptive drag reduction of a sphere using smart morphable skin |
| title_full | Adaptive drag reduction of a sphere using smart morphable skin |
| title_fullStr | Adaptive drag reduction of a sphere using smart morphable skin |
| title_full_unstemmed | Adaptive drag reduction of a sphere using smart morphable skin |
| title_short | Adaptive drag reduction of a sphere using smart morphable skin |
| title_sort | adaptive drag reduction of a sphere using smart morphable skin |
| topic | bluff body drag reduction flow control wake control |
| url | https://www.cambridge.org/core/product/identifier/S2633425925000078/type/journal_article |
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