蝴蝶翼面形状对绕流结构的影响

Shape of butterfly wing affects flow structures

蝴蝶的扑翼飞行因其相对翼展较大、扑翼频率低等特点引起广泛关注,尤其是具有越洋迁徙特性的蝴蝶更是备受瞩目。本文以天堂鸟翼凤蝶和黑脉金斑蝶这两种长距离迁徙蝴蝶作为研究原型,利用氢气泡流动显示技术研究这两种不同外形的蝴蝶翼面绕流结构随迎角的变化。在相同的实验条件下,两种模型翼面绕流均出现前缘涡、翼尖涡等流动结构,且绕流结构随迎角的变化趋势基本相同。但由于翼面外形的不同,两种模型在前缘涡的形态、强度及后翼面翼尖绕流结构等方面表现出一定的差异。

The flight of butterfly has received a great deal of attention owing mainly to its larger-scale wingspan and lower wing-beat frequency than some insects as fruit fly and bee, especially the species of butterfly which has the migratory habit. The present work investigates the difference of the flow structures between the plate models of Papilio ulysses and Danaus plexippus, two of the migratory butterflies, through hydrogen bubble visualization as the attach angle increases. When flow passes over the two butterfly models under the same experimental condition, the leading-edge vortices, wing-tip vortices and other flow structures all appear on both model wings. Further more, the development tendencies of flow structures for the two butterflies are similar to each other. Because of the difference between the shapes of the two model wings, some details of the flow field are not the same, such as the shape and the vortex strength of the leading-edge vortices, the wing-tip flow structure at the both side of the hindwings and so forth.