Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly
Unlike other insects, a butterfly uses a small amplitude of the wing-pitch motion for flight. From an analysis of the dynamics of real flying butterflies, we show that the restrained amplitude of the wing-pitch motion enhances the wake-capture effect so as to enhance forward propulsion. A numerical...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
The Royal Society
2021-08-01
|
| Series: | Royal Society Open Science |
| Subjects: | |
| Online Access: | https://royalsocietypublishing.org/doi/10.1098/rsos.202172 |
| _version_ | 1831571141693538304 |
|---|---|
| author | You-Jun Lin Sheng-Kai Chang Yu-Hsiang Lai Jing-Tang Yang |
| author_facet | You-Jun Lin Sheng-Kai Chang Yu-Hsiang Lai Jing-Tang Yang |
| author_sort | You-Jun Lin |
| collection | DOAJ |
| description | Unlike other insects, a butterfly uses a small amplitude of the wing-pitch motion for flight. From an analysis of the dynamics of real flying butterflies, we show that the restrained amplitude of the wing-pitch motion enhances the wake-capture effect so as to enhance forward propulsion. A numerical simulation refined with experimental data shows that, for a small amplitude of the wing-pitch motion, the shed vortex generated in the downstroke induces air in the wake region to flow towards the wings. This condition enables a butterfly to capture an induced flow and to acquire an additional forward propulsion, which accounts for more than 47% of the thrust generation. When the amplitude of the wing-pitch motion exceeds 45°, the flow induced by the shed vortex drifts away from the wings; it attenuates the wake-capture effect and causes the butterfly to lose a part of its forward propulsion. Our results provide one essential aerodynamic feature for a butterfly to adopt a small amplitude of the wing-pitch motion to enhance the wake-capture effect and forward propulsion. This work clarifies the variation of the flow field correlated with the wing-pitch motion, which is useful in the design of wing kinematics of a micro-aerial vehicle. |
| first_indexed | 2024-12-17T13:03:44Z |
| format | Article |
| id | doaj.art-9677c238ed0e4332b207b6a36710a204 |
| institution | Directory Open Access Journal |
| issn | 2054-5703 |
| language | English |
| last_indexed | 2024-12-17T13:03:44Z |
| publishDate | 2021-08-01 |
| publisher | The Royal Society |
| record_format | Article |
| series | Royal Society Open Science |
| spelling | doaj.art-9677c238ed0e4332b207b6a36710a2042022-12-21T21:47:17ZengThe Royal SocietyRoyal Society Open Science2054-57032021-08-018810.1098/rsos.202172Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterflyYou-Jun Lin0Sheng-Kai Chang1Yu-Hsiang Lai2Jing-Tang Yang3Department of Mechanical Engineering, National Taiwan University, Taipei 10617, TaiwanDepartment of Mechanical Engineering, National Taiwan University, Taipei 10617, TaiwanDepartment of Mechanical Engineering, National Taiwan University, Taipei 10617, TaiwanDepartment of Mechanical Engineering, National Taiwan University, Taipei 10617, TaiwanUnlike other insects, a butterfly uses a small amplitude of the wing-pitch motion for flight. From an analysis of the dynamics of real flying butterflies, we show that the restrained amplitude of the wing-pitch motion enhances the wake-capture effect so as to enhance forward propulsion. A numerical simulation refined with experimental data shows that, for a small amplitude of the wing-pitch motion, the shed vortex generated in the downstroke induces air in the wake region to flow towards the wings. This condition enables a butterfly to capture an induced flow and to acquire an additional forward propulsion, which accounts for more than 47% of the thrust generation. When the amplitude of the wing-pitch motion exceeds 45°, the flow induced by the shed vortex drifts away from the wings; it attenuates the wake-capture effect and causes the butterfly to lose a part of its forward propulsion. Our results provide one essential aerodynamic feature for a butterfly to adopt a small amplitude of the wing-pitch motion to enhance the wake-capture effect and forward propulsion. This work clarifies the variation of the flow field correlated with the wing-pitch motion, which is useful in the design of wing kinematics of a micro-aerial vehicle.https://royalsocietypublishing.org/doi/10.1098/rsos.202172butterfly flightwing-pitch motioninduced flowwake-capture effectforward propulsion |
| spellingShingle | You-Jun Lin Sheng-Kai Chang Yu-Hsiang Lai Jing-Tang Yang Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly Royal Society Open Science butterfly flight wing-pitch motion induced flow wake-capture effect forward propulsion |
| title | Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly |
| title_full | Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly |
| title_fullStr | Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly |
| title_full_unstemmed | Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly |
| title_short | Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly |
| title_sort | beneficial wake capture effect for forward propulsion with a restrained wing pitch motion of a butterfly |
| topic | butterfly flight wing-pitch motion induced flow wake-capture effect forward propulsion |
| url | https://royalsocietypublishing.org/doi/10.1098/rsos.202172 |
| work_keys_str_mv | AT youjunlin beneficialwakecaptureeffectforforwardpropulsionwitharestrainedwingpitchmotionofabutterfly AT shengkaichang beneficialwakecaptureeffectforforwardpropulsionwitharestrainedwingpitchmotionofabutterfly AT yuhsianglai beneficialwakecaptureeffectforforwardpropulsionwitharestrainedwingpitchmotionofabutterfly AT jingtangyang beneficialwakecaptureeffectforforwardpropulsionwitharestrainedwingpitchmotionofabutterfly |