Effects of Mach Number and Specific Heat Ratio on Low-Reynolds-Number Airfoil Flows
Effects of Mach Number and Specific Heat Ratio on Low-Reynolds-Number Airfoil Flows
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DOI：
10.2514/1.j053468
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发表时间：
2015-06-01
期刊：
影响因子：
2.5
通讯作者：
Asai, Keisuke
中科院分区：
文献类型：
--
作者：
Anyoji, Masayuki;Numata, Daiju;Asai, Keisuke
在低雷诺数（Re= 0.43 × 104 ~ 4.1 × 104）和高亚音速（M=0.1 ~ 0.6）条件下，研究了雷诺数、马赫数和气体组分（空气和CO2）对薄平板和NACA 0012-34翼型气动特性的影响。除了通过双组分平衡系统测量升力和阻力外，还应用压敏涂料技术测量模型表面的压力分布。对于平板，雷诺数对升力和阻力特性的影响不大，因为前缘分离泡的行为很简单;分离泡的长度随着迎角的增加而增加。相比之下，马赫数和比热比对气动性能的贡献很小。对于NACA 0012-34翼型，由于分离泡的形成、移动和破裂，升力曲线高度依赖于雷诺数，而压缩性只影响失速特性。比热容比对气动性能影响不大。两种翼型的共同点是，马赫数效应使层流-湍流转捩和分离剪切层的再附着延迟。
The effects of Reynolds number, Mach number, and gas species (air and CO2) on aerodynamic characteristics of a thin flat plate and a NACA 0012-34 airfoil were investigated under low-Reynolds-number (Re=0.43x104 to 4.1x104) and high-subsonic-flow (M=0.1 to 0.6) conditions. In addition to lift and drag measurements by a two-component balance system, the pressure-sensitive paint technique was applied to measure pressure profiles on the model surface. For the flat plate, the Reynolds number moderately affects the lift and drag characteristics because of a simple behavior of the leading-edge separation bubble; the length of the separation bubble increases as the angle of attack increases. By contrast, the Mach number and specific heat ratio contribute little to the aerodynamic performance. For the NACA 0012-34 airfoil, the lift curves are highly dependent on the Reynolds number because of the formation, shift, and burst of the separation bubble, whereas the compressibility affects only the stall characteristics. The specific heat ratio has little effect on the aerodynamic performance. In common for both airfoils, it was observed that the Mach-number effect allows for the delay of a laminar-turbulent transition and reattachment of the separated shear layer.