Numerical investigation of non-planarity and relative motion for bionic slotted wings
Bird wings have split primary feathers that extend out from the wing surface. This structure is called the wingtip slot, which is recognized as a product of bird evolution to improve flight performance. In this paper, numerical simulations based on RANS (Reynolds-averaged Navier–Stokes) equations ar...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
AIP Publishing LLC
2023-08-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/5.0156163 |
| _version_ | 1827821739686494208 |
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| author | Dan Liu Jiaao Cheng Bifeng Song Wenqing Yang Dong Xue |
| author_facet | Dan Liu Jiaao Cheng Bifeng Song Wenqing Yang Dong Xue |
| author_sort | Dan Liu |
| collection | DOAJ |
| description | Bird wings have split primary feathers that extend out from the wing surface. This structure is called the wingtip slot, which is recognized as a product of bird evolution to improve flight performance. In this paper, numerical simulations based on RANS (Reynolds-averaged Navier–Stokes) equations are conducted to examine and understand the influence of wingtip slots on six wings at Re = 100 000. The overlapping grid method, driven by an in-house UDF (User Defined Function), is used to model the motion of the bionic slotted wings. The motion law of the winglets is improved based on the law extracted from a level-flying bald eagle. Then the aerodynamic force, pressure distribution, vorticity contours, wake stream, and other flow structures of the slotted wings with different layouts were compared and analyzed. The results show a significant increase in aerodynamic force when the slotted wingtips are employed. The maximum lift-to-drag ratio is also improved in our designed wing model with a non-planar wingtip by a maximum of 34% from the base wing. Each winglet works as a single wing due to the existence of slots, with a chordwise pressure distribution similar to that of the main wing. The vortex structures of slotted wings show expressive changes in the tip vortex as compared with the base wing. Additionally, an innovative bionic slotted wing is proposed with a dynamic wingtip that forms varying gaps between winglets. Due to the collective mechanism of aerodynamic interaction among multiple winglets for the innovative wing, it acquires the optimal time-averaged force during a flapping period. As expected, the slotted wingtip reduces the main wingtip vortex intensity and creates weaker vortices. The non-planarity and relative motion of the wingtip strengthen its weakening effect on the wingtip vortex and wake. |
| first_indexed | 2024-03-12T01:48:21Z |
| format | Article |
| id | doaj.art-6bbd999ea4984a199385156427a56922 |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-03-12T01:48:21Z |
| publishDate | 2023-08-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-6bbd999ea4984a199385156427a569222023-09-08T16:03:31ZengAIP Publishing LLCAIP Advances2158-32262023-08-01138085322085322-1710.1063/5.0156163Numerical investigation of non-planarity and relative motion for bionic slotted wingsDan Liu0Jiaao Cheng1Bifeng Song2Wenqing Yang3Dong Xue4Chinese Flight Test Establishment, Xi’an 710089, ChinaChinese Flight Test Establishment, Xi’an 710089, ChinaNational Key Laboratory of Science and Technology on Aerodynamic Design and Research, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, ChinaNational Key Laboratory of Science and Technology on Aerodynamic Design and Research, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, ChinaNational Key Laboratory of Science and Technology on Aerodynamic Design and Research, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, ChinaBird wings have split primary feathers that extend out from the wing surface. This structure is called the wingtip slot, which is recognized as a product of bird evolution to improve flight performance. In this paper, numerical simulations based on RANS (Reynolds-averaged Navier–Stokes) equations are conducted to examine and understand the influence of wingtip slots on six wings at Re = 100 000. The overlapping grid method, driven by an in-house UDF (User Defined Function), is used to model the motion of the bionic slotted wings. The motion law of the winglets is improved based on the law extracted from a level-flying bald eagle. Then the aerodynamic force, pressure distribution, vorticity contours, wake stream, and other flow structures of the slotted wings with different layouts were compared and analyzed. The results show a significant increase in aerodynamic force when the slotted wingtips are employed. The maximum lift-to-drag ratio is also improved in our designed wing model with a non-planar wingtip by a maximum of 34% from the base wing. Each winglet works as a single wing due to the existence of slots, with a chordwise pressure distribution similar to that of the main wing. The vortex structures of slotted wings show expressive changes in the tip vortex as compared with the base wing. Additionally, an innovative bionic slotted wing is proposed with a dynamic wingtip that forms varying gaps between winglets. Due to the collective mechanism of aerodynamic interaction among multiple winglets for the innovative wing, it acquires the optimal time-averaged force during a flapping period. As expected, the slotted wingtip reduces the main wingtip vortex intensity and creates weaker vortices. The non-planarity and relative motion of the wingtip strengthen its weakening effect on the wingtip vortex and wake.http://dx.doi.org/10.1063/5.0156163 |
| spellingShingle | Dan Liu Jiaao Cheng Bifeng Song Wenqing Yang Dong Xue Numerical investigation of non-planarity and relative motion for bionic slotted wings AIP Advances |
| title | Numerical investigation of non-planarity and relative motion for bionic slotted wings |
| title_full | Numerical investigation of non-planarity and relative motion for bionic slotted wings |
| title_fullStr | Numerical investigation of non-planarity and relative motion for bionic slotted wings |
| title_full_unstemmed | Numerical investigation of non-planarity and relative motion for bionic slotted wings |
| title_short | Numerical investigation of non-planarity and relative motion for bionic slotted wings |
| title_sort | numerical investigation of non planarity and relative motion for bionic slotted wings |
| url | http://dx.doi.org/10.1063/5.0156163 |
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