Drag reduction mechanisms on a generic square-back vehicle using an optimised yaw-insensitive base cavity.
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| Title: | Drag reduction mechanisms on a generic square-back vehicle using an optimised yaw-insensitive base cavity. |
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| Authors: | Urquhart, Magnus1 (AUTHOR) magnus.urquhart@chalmers.se, Varney, Max2 (AUTHOR), Sebben, Simone1 (AUTHOR), Passmore, Martin2 (AUTHOR) |
| Source: | Experiments in Fluids. Dec2021, Vol. 62 Issue 12, p1-21. 21p. |
| Subjects: | Drag reduction, Cross-flow (Aerodynamics), Particle image velocimetry, Drag (Aerodynamics), Wind tunnels, Flow separation |
| Abstract: | Regulations on global greenhouse gas emission are driving the development of more energy-efficient passenger vehicles. One of the key factors influencing energy consumption is the aerodynamic drag where a large portion of the drag is associated with the base wake. Environmental conditions such as wind can increase the drag associated with the separated base flow. This paper investigates an optimised yaw-insensitive base cavity on a square-back vehicle in steady crosswind. The test object is a simplified model scale bluff body, the Windsor geometry, with wheels. The model is tested experimentally with a straight cavity and a tapered cavity. The taper angles have been optimised numerically to improve the robustness to side wind in relation to drag. Base pressures and tomographic Particle Image Velocimetry of the full wake were measured in the wind tunnel. The results indicate that a cavity decreases the crossflow within the wake, increasing base pressure, therefore lowering drag. The additional optimised cavity tapering further reduces crossflow and results in a smaller wake with less losses. The overall wake unsteadiness is reduced by the cavity by minimising mixing in the shear layers as well as dampening wake motion. However, the coherent wake motions, indicative of a balanced wake, are increased by the investigated cavities. [ABSTRACT FROM AUTHOR] |
| Copyright of Experiments in Fluids is the property of Springer Nature 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: 154247759 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Drag reduction mechanisms on a generic square-back vehicle using an optimised yaw-insensitive base cavity. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Urquhart%2C+Magnus%22">Urquhart, Magnus</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> magnus.urquhart@chalmers.se</i><br /><searchLink fieldCode="AR" term="%22Varney%2C+Max%22">Varney, Max</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Sebben%2C+Simone%22">Sebben, Simone</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Passmore%2C+Martin%22">Passmore, Martin</searchLink><relatesTo>2</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Experiments+in+Fluids%22">Experiments in Fluids</searchLink>. Dec2021, Vol. 62 Issue 12, p1-21. 21p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Drag+reduction%22">Drag reduction</searchLink><br /><searchLink fieldCode="DE" term="%22Cross-flow+%28Aerodynamics%29%22">Cross-flow (Aerodynamics)</searchLink><br /><searchLink fieldCode="DE" term="%22Particle+image+velocimetry%22">Particle image velocimetry</searchLink><br /><searchLink fieldCode="DE" term="%22Drag+%28Aerodynamics%29%22">Drag (Aerodynamics)</searchLink><br /><searchLink fieldCode="DE" term="%22Wind+tunnels%22">Wind tunnels</searchLink><br /><searchLink fieldCode="DE" term="%22Flow+separation%22">Flow separation</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Regulations on global greenhouse gas emission are driving the development of more energy-efficient passenger vehicles. One of the key factors influencing energy consumption is the aerodynamic drag where a large portion of the drag is associated with the base wake. Environmental conditions such as wind can increase the drag associated with the separated base flow. This paper investigates an optimised yaw-insensitive base cavity on a square-back vehicle in steady crosswind. The test object is a simplified model scale bluff body, the Windsor geometry, with wheels. The model is tested experimentally with a straight cavity and a tapered cavity. The taper angles have been optimised numerically to improve the robustness to side wind in relation to drag. Base pressures and tomographic Particle Image Velocimetry of the full wake were measured in the wind tunnel. The results indicate that a cavity decreases the crossflow within the wake, increasing base pressure, therefore lowering drag. The additional optimised cavity tapering further reduces crossflow and results in a smaller wake with less losses. The overall wake unsteadiness is reduced by the cavity by minimising mixing in the shear layers as well as dampening wake motion. However, the coherent wake motions, indicative of a balanced wake, are increased by the investigated cavities. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Experiments in Fluids is the property of Springer Nature 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: 10.1007/s00348-021-03334-0 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 21 StartPage: 1 Subjects: – SubjectFull: Drag reduction Type: general – SubjectFull: Cross-flow (Aerodynamics) Type: general – SubjectFull: Particle image velocimetry Type: general – SubjectFull: Drag (Aerodynamics) Type: general – SubjectFull: Wind tunnels Type: general – SubjectFull: Flow separation Type: general Titles: – TitleFull: Drag reduction mechanisms on a generic square-back vehicle using an optimised yaw-insensitive base cavity. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Urquhart, Magnus – PersonEntity: Name: NameFull: Varney, Max – PersonEntity: Name: NameFull: Sebben, Simone – PersonEntity: Name: NameFull: Passmore, Martin IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 12 Text: Dec2021 Type: published Y: 2021 Identifiers: – Type: issn-print Value: 07234864 Numbering: – Type: volume Value: 62 – Type: issue Value: 12 Titles: – TitleFull: Experiments in Fluids Type: main |
| ResultId | 1 |
