不同几何形状的自振后缘襟翼对翼型自噪声的影响
Effect of different geometries of self-oscillating trailing-edge flaplets on aerofoil self-noise
摘要：
本文介绍了一个标准的NACA 0012翼型与附加的自激振荡被动襟翼连接到后缘的声学研究。在勃兰登堡技术大学的消声风洞中进行了不同襟翼几何形状的试验，试验雷诺数为基于弦的雷诺数，$Re_c = 100,000 - 900,000$为三种几何攻角$α_g = 0^\circ, 10^\circ$和$15^\circ$。据观察，所有flaplet配置减少音调噪声和减少这种噪声分量的关键几何参数是flaplet的宽度。测试的最窄配置几乎完全消除了音调噪音，使$α_g = 10^\circ$的整个$Re_c$范围内的平均总体声压级降低高达9 dB。还观察到，在低频区域中，可以通过调谐振荡片状物的固有频率来实现进一步的噪声降低。当片状物的固有频率增加时，噪声频谱中由此受影响的频率范围移动到较高频率，反之亦然。因此，我们提出了一种新的方法，目标特定的频率在被动翼型自噪声消除。
英文摘要：
This paper presents an acoustic study of a standard NACA 0012 aerofoil with additional self-oscillating passive flaplets attached to the trailing edge. The tests with varying geometries of the flaplets were conducted in the anechoic wind tunnel at Brandenburg University of Technology, at chord based Reynolds numbers, $Re_c = 100,000 - 900,000$ at three geometric angles of attack $α_g = 0^\circ, 10^\circ$ and $15^\circ$. It was observed that all flaplet configurations reduce tonal noise and that the key geometric parameter to reduce this noise component is the width of the flaplets. The narrowest configuration tested almost completely removed the tonal noise, leading to an average overall sound pressure level reduction of up to 9 dB across the entire $Re_c$ range at $α_g = 10^\circ$. It was also observed that, in the low frequency regime, a further noise reduction can be achieved by tuning the natural frequency of the oscillating flaplets. The thereby affected frequency range in the noise spectrum moves to higher frequencies when the natural frequency of the flaplets is increased and vice versa. Hence we show a novel way to target specific frequencies in passive aerofoil self-noise cancellation.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
