Aerodynamic Characteristics at Low Reynolds Numbers for Wings of Various Planforms
Aerodynamic Characteristics at Low Reynolds Numbers for Wings of Various Planforms
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DOI：
10.2514/1.j050071
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发表时间：
2011-06
期刊：
影响因子：
2.5
通讯作者：
M. Okamoto;A. Azuma
中科院分区：
文献类型：
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作者：
M. Okamoto;A. Azuma
通过风洞试验研究了低雷诺数（约1 × 104）条件下不同翼型的气动特性。这些低雷诺数对应于小生物（如昆虫）的飞行。在这项研究中使用了不同纵横比的椭圆、矩形和三角形平台，以及纵横比为4的后掠矩形（平行四边形）机翼。所有型号的机翼部分都是薄矩形翼型。空气动力（升力和阻力）和俯仰力矩作用在机翼上的测量迎角范围很广（包括最大90度）。高展弦比机翼即使在低迎角下也能获得升力系数的非线性特征，而低展弦比机翼则能获得较小的升力斜率和较大的最大升力系数。阻力系数和俯仰力矩系数也表现出非线性特征。基于翼弦的雷诺数的影响相对较小，但采用油膜法和烟丝法的流动显示在低雷诺数流动中观察到一个明显的现象。
The aerodynamic characteristics of various wing planforms at low Reynolds numbers (about 1 x 10 4 ) were studied by conducting wind-tunnel tests. These low Reynolds numbers correspond to the flights of small creatures, such as insects. Elliptical, rectangular, and triangular planforms with various aspect ratios were used in this study, as well as a swept rectangular (parallelogram) wing with an aspect ratio of four. The wing sections of all models were thin rectangular airfoils. The aerodynamic forces (lift and drag) and the pitching moment acting on the wing were measured for a wide range of angles of attack (including the maximum of 90 deg). Nonlinear characteristics of the lift coefficient were obtained, even at low angles of attack for high-aspect-ratio wings, whereas a small lift slope and a large maximum lift coefficient were obtained for low-aspect-ratio wings. The drag and the pitching moment coefficients also exhibited nonlinear characteristics. The effect of the Reynolds number based on the wing chord was comparatively small, but a distinctive phenomenon in low-Reynolds-number flow was observed in flow visualization using oil-film and smoke-wire methods.