Abstract An experimental study of a simple NACA 0012 airfoil fitted with two different flap profiles was carried out to characterize their aerodynamic and aeroacoustic performance. The airfoil with a flap deflection angle of β = 10 ° was tested for a wide range of angles of attack at a chord-based Reynolds number of Re c = 2.6 × 10 5 . The aerodynamic lift and drag measurements show improved lift-to-drag performance for the morphed flap airfoil compared to the hinged flap airfoil at low angles of attack. Surface flow visualization and boundary layer measurements on the suction surface of the flap show delayed separation for the morphed flap airfoil. Higher-order moments of the wall pressure fluctuations were also used to observe the flow separation over the flap. Additionally, Particle Image Velocimetry was also used to study the flow over the flap and at the airfoil wake. Flow measurements showed that the downstream wake development could be significantly influenced by the flap camber. The mean velocity contours at the wake showed increased wake velocity deficit and turbulent kinetic energy for the morphed flap airfoil. The turbulent kinetic energy results displayed a characteristic double peak behavior which was also the dominant characteristics of the streamwise Reynolds shear stress component. Near-field unsteady surface pressure fluctuations and far-field noise measurements show reduced point spectra and noise levels for morphed flap configuration at low angles of attack but considerably increased noise levels at high angles of attack compared to hinged flap configuration.

中文翻译：

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装有变形后缘的翼型的声学和流动特性

摘要 对装有两种不同襟翼轮廓的简单 NACA 0012 翼型进行了实验研究，以表征其空气动力学和气动声学性能。在基于弦的雷诺数 Re c = 2.6 × 10 5 下，对襟翼偏转角为 β = 10° 的翼型进行了广泛的攻角测试。气动升力和阻力测量表明，与铰接襟翼翼型相比，变形襟翼翼型在低迎角下的升阻性能有所提高。襟翼吸力表面的表面流动可视化和边界层测量显示变形襟翼翼型的延迟分离。壁压力波动的高阶矩也用于观察瓣上的流动分离。此外，粒子图像测速法也用于研究襟翼上和翼型尾流处的流动。流量测量表明，襟翼弯度会显着影响下游尾流的发展。尾流处的平均速度等值线显示变形襟翼翼型的尾流速度不足和湍流动能增加。湍流动能结果显示出典型的双峰行为，这也是流向雷诺剪切应力分量的主要特征。近场非稳态表面压力波动和远场噪声测量表明，与铰链襟翼结构相比，变形襟翼结构在低迎角下的点谱和噪声水平降低，但在高迎角下的噪声水平显着增加。流量测量表明，襟翼弯度会显着影响下游尾流的发展。尾流处的平均速度等值线显示变形襟翼翼型的尾流速度不足和湍流动能增加。湍流动能结果显示出典型的双峰行为，这也是流向雷诺剪切应力分量的主要特征。近场非稳态表面压力波动和远场噪声测量表明，与铰链襟翼结构相比，变形襟翼结构在低迎角下的点谱和噪声水平降低，但在高迎角下的噪声水平显着增加。流量测量表明，襟翼弯度会显着影响下游尾流的发展。尾流处的平均速度等值线显示变形襟翼翼型的尾流速度不足和湍流动能增加。湍流动能结果显示出典型的双峰行为，这也是流向雷诺剪切应力分量的主要特征。近场非稳态表面压力波动和远场噪声测量表明，与铰链襟翼结构相比，变形襟翼结构在低迎角下的点谱和噪声水平降低，但在高迎角下的噪声水平显着增加。尾流处的平均速度等值线显示变形襟翼翼型的尾流速度不足和湍流动能增加。湍流动能结果显示出典型的双峰行为，这也是流向雷诺剪切应力分量的主要特征。近场非稳态表面压力波动和远场噪声测量表明，与铰链襟翼结构相比，变形襟翼结构在低迎角下的点谱和噪声水平降低，但在高迎角下的噪声水平显着增加。尾流处的平均速度等值线显示变形襟翼翼型的尾流速度不足和湍流动能增加。湍流动能结果显示出典型的双峰行为，这也是流向雷诺剪切应力分量的主要特征。近场非稳态表面压力波动和远场噪声测量表明，与铰链襟翼结构相比，变形襟翼结构在低迎角下的点谱和噪声水平降低，但在高迎角下的噪声水平显着增加。湍流动能结果显示出典型的双峰行为，这也是流向雷诺剪切应力分量的主要特征。近场非稳态表面压力波动和远场噪声测量表明，与铰链襟翼结构相比，变形襟翼结构在低迎角下的点谱和噪声水平降低，但在高迎角下的噪声水平显着增加。湍流动能结果显示出典型的双峰行为，这也是流向雷诺剪切应力分量的主要特征。近场非稳态表面压力波动和远场噪声测量表明，与铰链襟翼结构相比，变形襟翼结构在低迎角下的点谱和噪声水平降低，但在高迎角下的噪声水平显着增加。