Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous Coatings
This paper presents a numerical study on the impact of partial leeward porous coatings on the drag of circular cylinders in cross-flow. Porous coatings are receiving increasing attention for their potential in passive flow control. An unsteady Reynolds-averaged Navier–Stokes model was developed that...
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MDPI AG
2021-08-01
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| Online Access: | https://www.mdpi.com/2311-5521/6/8/289 |
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| author | Imogen Guinness Tim Persoons |
| author_facet | Imogen Guinness Tim Persoons |
| author_sort | Imogen Guinness |
| collection | DOAJ |
| description | This paper presents a numerical study on the impact of partial leeward porous coatings on the drag of circular cylinders in cross-flow. Porous coatings are receiving increasing attention for their potential in passive flow control. An unsteady Reynolds-averaged Navier–Stokes model was developed that agreed well with the numerical and experimental literature. Using the two-equation shear stress transport <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>k</mi><mo>−</mo><mi>ω</mi></mrow></semantics></math></inline-formula> turbulence model, 2D flow around a circular cylinder was simulated at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>e</mi></mrow></semantics></math></inline-formula> = <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>4.2</mn><mo>×</mo><msup><mn>10</mn><mn>4</mn></msup></mrow></semantics></math></inline-formula> with five different angles of partial leeward porous coatings and a full porous coating. For coating angles below <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>130</mn><mo>∘</mo></msup></semantics></math></inline-formula>, the coating resulted in an increase in pressure on the leeward side of the cylinder. There was a significant reduction in the fluctuation of the pressure and aerodynamic forces and a damping effect on vortex shedding. Flow separation occurred earlier; the wake was widened; and there was a decrease in turbulence intensity at the outlet. A reduction of drag between 5 and 16% was measured, with the maximum at a 70<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula> coating angle. The results differed greatly for a full porous coating and a 160<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula> coating, which were found to cause an increase in drag of 42% and 43%, respectively. The results showed that leeward porous coatings have a clear drag-reducing potential, with possibilities for further research into the optimum configuration. |
| first_indexed | 2024-03-10T08:50:09Z |
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| language | English |
| last_indexed | 2024-03-10T08:50:09Z |
| publishDate | 2021-08-01 |
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| spelling | doaj.art-d887b5f820e24f31b1e7d8c593821e292023-11-22T07:37:02ZengMDPI AGFluids2311-55212021-08-016828910.3390/fluids6080289Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous CoatingsImogen Guinness0Tim Persoons1Department of Mechanical, Manufacturing & Biomedical Engineering, Trinity College, University of Dublin, Parsons Building, Dublin 2, IrelandDepartment of Mechanical, Manufacturing & Biomedical Engineering, Trinity College, University of Dublin, Parsons Building, Dublin 2, IrelandThis paper presents a numerical study on the impact of partial leeward porous coatings on the drag of circular cylinders in cross-flow. Porous coatings are receiving increasing attention for their potential in passive flow control. An unsteady Reynolds-averaged Navier–Stokes model was developed that agreed well with the numerical and experimental literature. Using the two-equation shear stress transport <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>k</mi><mo>−</mo><mi>ω</mi></mrow></semantics></math></inline-formula> turbulence model, 2D flow around a circular cylinder was simulated at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>e</mi></mrow></semantics></math></inline-formula> = <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>4.2</mn><mo>×</mo><msup><mn>10</mn><mn>4</mn></msup></mrow></semantics></math></inline-formula> with five different angles of partial leeward porous coatings and a full porous coating. For coating angles below <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>130</mn><mo>∘</mo></msup></semantics></math></inline-formula>, the coating resulted in an increase in pressure on the leeward side of the cylinder. There was a significant reduction in the fluctuation of the pressure and aerodynamic forces and a damping effect on vortex shedding. Flow separation occurred earlier; the wake was widened; and there was a decrease in turbulence intensity at the outlet. A reduction of drag between 5 and 16% was measured, with the maximum at a 70<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula> coating angle. The results differed greatly for a full porous coating and a 160<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula> coating, which were found to cause an increase in drag of 42% and 43%, respectively. The results showed that leeward porous coatings have a clear drag-reducing potential, with possibilities for further research into the optimum configuration.https://www.mdpi.com/2311-5521/6/8/289drag reductionporous media flowURANS CFD modellingvortex shedding<i>k</i>-ω SST |
| spellingShingle | Imogen Guinness Tim Persoons Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous Coatings Fluids drag reduction porous media flow URANS CFD modelling vortex shedding <i>k</i>-ω SST |
| title | Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous Coatings |
| title_full | Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous Coatings |
| title_fullStr | Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous Coatings |
| title_full_unstemmed | Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous Coatings |
| title_short | Passive Flow Control for Drag Reduction on a Cylinder in Cross-Flow Using Leeward Partial Porous Coatings |
| title_sort | passive flow control for drag reduction on a cylinder in cross flow using leeward partial porous coatings |
| topic | drag reduction porous media flow URANS CFD modelling vortex shedding <i>k</i>-ω SST |
| url | https://www.mdpi.com/2311-5521/6/8/289 |
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