蝴蝶撲翼姿態對飛行影響之研究

The influence of the flapping wing motion on the flight of butterflies

王相博(Xiang-Bo Wang)

指導教授 ： 楊鏡堂

國立臺灣大學/工學院/機械工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.02521

摘要

本文以枯葉蝶(Indian Leaf Butterfly, Kallima inachus)為實驗對象，研究蝴蝶在撲翼飛行時，身體動作與周圍流場對其操控性飛行的影響。本研究探討枯葉蝶飛行時所採用的物理機制，結果可以應用在仿生撲翼機構的設計上，改進微型飛行器的性能。
本研究利用高速攝影機拍攝枯葉蝶的自由飛行動作，藉此紀錄特徵點的移動軌跡，並算出其移動速度。實驗同時以粒子影像測速儀觀察枯葉蝶飛行時的周圍流場，測量其流場結構並估算推進力。藉由動作與流場的分析，探討枯葉蝶飛行時採用的推進策略。
根據實驗的結果，可以利用特徵點的速度變化，將枯葉蝶的飛行動作區分為四個階段，並對應至無因次時間。由動作的分析可以看出，枯葉蝶在拍翅時，翅膀經歷了一定的變形。前翼與後翼之間由於翅膀可撓性而使拍翅相位不一致；這個差異影響了周圍的射流位置，同時在前翼之間形成凹槽結構；使枯葉蝶能夠在拋翼階段迅速建立翼前緣渦漩。實驗亦觀察到枯葉蝶在飛行時會配合身體的擺動；由於枯葉蝶的前後翼彼此疊合，翅膀的扭轉運動受到一定的限制。然而在翅膀拍撲的同時，這身體擺動的動作可以達到扭轉翅膀的效果，加強翅膀與周圍流場間的相對速度。根據流場的量測結果，本研究同時利用渦漩環理論模式進行推進力的估計，得出在拋翼階段時有約體重74%的推進力量；估計出的推進力量雖不足，但其趨勢仍可以看出拋翼與拍翼動作對枯葉蝶飛行的重要性。在流場的觀察中，本研究亦發現渦漩環與周圍流場結構的互動關係，顯示出枯葉蝶飛行時回收流場能量的智慧。

關鍵字

蝴蝶 ； 拋翼與拍翼 ； 翼前緣渦流 ； 渦漩環理論模式

並列摘要

This study is aimed to investigate the flapping wing flight of butterflies. The influence of the flapping wing motion and flow structure on maneuvering flight of Indian Leaf Butterfly was explored. This investigation of the flight of butterfly can be applied on the design of biomimetic flapping mechanism, improving the performance of micro aerial vehicle. To achieve this goal, I recorded the free flight of Indian Leaf Butterfly by high speed camera, and found the variation of trajectory and velocity of characteristic points. With the measurement of the flow field on the flight of Indian Leaf Butterfly, the force generated by the vortex ring was also estimated. According to the velocity variation of characteristic points, the flapping wing motion can be distinguished into four stages with specific normalized time. The wing deformation was also observed, which caused a phase lag between fore wing and hind wing. This phase lag influenced the position of the jet, and introduced a valley-structure between the two fore wings. With these two effects, the leading edge vortex can be established rapidly during the fling motion. The swing motion of the body accompanied with the flight was also investigated. These swing motion can be viewed as a pitch rotation of the wing, enhancing the relative velocity between wings and flow field. Based on the measurement of the flow field, the force generated by the vortex ring was estimated to be 75% of the weight of butterfly. The force estimated by the vortex ring model was not sufficient. However, the importance of clap and fling mechanism on the flight of butterfly can still be discovered. On the other hand, the flow filed measurement revealed the interaction between vortex ring and nearby flow structure, which can be viewed as wisdom of energy recycling for Indian Leaf Butterfly.

並列關鍵字

butterfly ； clap and fling ； leading edge vortex ； vortex ring model

參考文獻

蘇健元 2013 綠繡眼高操控性飛行之生物力學研究. 台灣大學機械工程學系博士論文.

章聿珩 2010 運動學參數對鳥類拍撲翼之升力影響. 台灣大學機械工程學系碩士論文.

Bomphrey, R. J., N. J. Lawson, et al. (2006). "Application of digital particle image velocimetry to insect aerodynamics: measurement of the leading-edge vortex and near wake of a Hawkmoth." Experiments in Fluids 40(4): 546-554.

Brodsky, A. K. (1991). "Vortex Formation in the Tethered Flight of the Peacock Butterfly Inachis Io L (Lepidoptera, Nymphalidae) and Some Aspects of Insect Flight Evolution." Journal of Experimental Biology 161: 77-95.

Combes, S. A. and T. L. Daniel (2003). "Flexural stiffness in insect wings I. Scaling and the influence of wing venation." Journal of Experimental Biology 206(17): 2979-2987.