Aspect-Ratio Effects on Aeromechanics of Membrane Wings at Moderate Reynolds Numbers
Aspect-Ratio Effects on Aeromechanics of Membrane Wings at Moderate Reynolds Numbers
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DOI：
10.2514/1.j053522
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发表时间：
2015-03-01
期刊：
影响因子：
2.5
通讯作者：
Ganapathisubramani, B.
中科院分区：
文献类型：
--
作者：
Bleischwitz, R.;de Kat, R.;Ganapathisubramani, B.
中等雷诺数Re= 67，500时薄膜机翼的展弦比影响气动性能以及薄膜变形。风洞实验使用三种不同的低展弦比机翼（展弦比为1、1.5和2）进行。空气动力学性能是由力和力矩测量确定的，这些测量是使用六分量力传感器进行的。膜变形是使用摄影测量获得的。空气动力学性能和膜变形的平均值和非定常效应进行了研究。平均挠度结果表明，低展弦比薄膜机翼沿翼展方向沿着表现出确定的U形挠度，而高展弦比薄膜机翼翼尖的变形逐渐增大。膜的主要弦向振动模式及其频谱内容表明，较低的纵横比表现出较高的模式形状和频率，可能是由于增加的下洗，这延迟了涡脱落到更高的发病率的影响。膜运动的主导模式的频率被发现与升力和阻力波动的频率。
The aspect ratio of a membrane wing at moderate Reynolds number Re=67,500 affects aerodynamic performance as well as membrane deformations. Wind-tunnel experiments are conducted using three different low-aspect-ratio wings (aspect ratios of 1, 1.5, and 2). Aerodynamic performance is determined from force and moment measurements, which are performed using a six-component force transducer. Membrane deformations are obtained using photogrammetry. Mean values and unsteady effects are examined for both aerodynamic performance and membrane deformations. Mean deflection results indicate that lower-aspect-ratio membrane wings show defined U-shape deflections along the span, whereas higher aspect ratios display a progressive rise in deformation to the wing tip. Dominant chordwise vibration modes of the membrane and their spectral content show that lower aspect ratios exhibit higher mode shapes and frequencies, likely caused by increased downwash, which delays the influence of vortex shedding into higher incidences. The frequencies of the dominant modes in membrane motions are found to correlate with the frequencies of lift and drag fluctuations.