Aerodynamic effects of varying solid surface area of bristled wings performing clap and fling
Aerodynamic effects of varying solid surface area of bristled wings performing clap and fling
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DOI：
10.1088/1748-3190/ab1a00
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发表时间：
2019-07-01
影响因子：
3.4
通讯作者：
Santhanakrishnan, Arvind
中科院分区：
文献类型：
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作者：
Ford, Mitchell P.;Kasoju, Vishwa T.;Santhanakrishnan, Arvind
体长小于 2 毫米的最小飞行昆虫表现出对由带有长鬃毛的薄膜组成的翅膀的明显偏好，并使用拍击和投掷运动学来增加雷诺数 (Re) 约为 10 时的升力。鬃毛翅膀已被证明可以减少拍击和投掷中的阻力，但几个鬃毛翅膀几何变量的空气动力学作用仍不清楚。本研究研究了改变膜面积 (A(M)) 与机翼总面积 (A(T)) 的比率对 Re 为 10 的拍击和投掷过程中产生的空气动力和流动结构的影响。我们还研究了将刚毛翅膀缩放至 Re = 120 的空气动力学后果，这与果蝇的飞行有关。我们分析了已发表的 25 种蓟马（缨翅目）的前翅图像，发现 A(M)/A(T) 范围为 14% 至 27%，而之前报道的较小体型仙蝇（膜翅目）的 A(M)/A(T) 范围为 11% 至 88%。这些数据用于开发 A(M)/A(T) 范围为 15% 至 100% 的物理鬃毛机翼模型，并在动态缩放的机器人拍击和投掷模型中进行了测试。在所有 Re 下，与实心机翼相比，刚毛机翼产生的升力系数（CO）略低，但阻力显着降低。在 Re = 10 时，峰值升力与峰值阻力之比的最大值由具有类似于蓟马前翅的 A(M)/A(T) 的机翼模型生成（15% 至 30%）。在拍击和投掷过程中，前缘涡流和后缘涡流的循环随着 A(M)/A(T) 的减小而减小Re = 10 时。与 Re = 10 相比，翼尖附近的弦向循环减少、涡流脱落以及拍击和投掷产生的流结构之间的相互作用导致在 Re = 120 时通过拍击和投掷产生的 C-L 降低。与 Re = 10 相比，拍击和投掷在 Re = 120 时变得不太有利，无论鬃毛机翼提供的阻力如何减少。
The smallest flying insects with body lengths under 2 mm show a marked preference for wings consisting of a thin membrane with long bristles, and the use of clap and fling kinematics to augment lift at Reynolds numbers (Re) of approximately 10. Bristled wings have been shown to reduce drag forces in clap and fling, but the aerodynamic roles of several bristled wing geometric variables remain unclear. This study examines the effects of varying the ratio of membrane area (A(M)) to total wing area (A(T)) on aerodynamic forces and flow structures generated during clap and fling at Re on the order of 10. We also examine the aerodynamic consequences of scaling bristled wings to Re = 120, relevant to flight of fruit flies. We analyzed published forewing images of 25 species of thrips (Thysanoptera) and found that A(M)/A(T) ranged from 14% to 27%, as compared to 11% to 88% previously reported for smaller-sized fairyflies (Hymenoptera). These data were used to develop physical bristled wing models with A(M)/A(T) ranging from 15% to 100%, which were tested in a dynamically scaled robotic clap and fling model. At all Re, bristled wings produced slightly lower lift coefficients (CO when compared to solid wings, but provided significant drag reduction. At Re = 10, largest values of peak lift over peak drag ratios were generated by wing models with A(M)/A(T) similar to thrips forewings (15% to 30%). Circulation of the leading edge vortex and trailing edge vortex decreased with decreasing A(M)/A(T) during clap and fling at Re = 10. Decreased chordwise circulation near the wing tip, vortex shedding, and interaction between flow structures from clap with those from fling resulted in lowering C-L generated via clap and fling at Re = 120 as compared to Re = 10. Clap and fling becomes less beneficial at Re = 120, regardless of the drag reduction provided by bristled wings.