基于仿生学结构的翼型降噪实验研究

An Experimental Study on the Noise Reduction With Bionic Airfoil

本文运用平面传声器阵列研究了翼型常规尾缘、锯齿形尾缘及波浪形前缘的气动噪声,并在全消声室环境下实验研究了仿生学前缘、尾缘的降噪效果。设计的传声器阵列是同一平面上的单支螺旋线结构,用于二维平面声源定位。实验结果表明:在低湍流度、自由来流情况下,尾缘噪声超过前缘噪声,是翼型噪声的最主要来源,锯齿形尾缘能够有效地降低翼型的尾缘噪声;在较大的宽频范围内,锯齿形尾缘均起到很好的降噪效果,尾缘最大降噪量可以达到10 dB。而波浪形前缘的波长越短,对翼型尾缘的降噪量越明显;波浪形前缘对尾缘噪声的降噪效果在低频时较为明显,而在高频情况下,可以忽略不计。对于湍流-翼型干涉噪声的研究表明:湍流-翼型干涉噪声主要发生于翼型前缘,其声压级远大于尾缘;且锯齿尾缘几乎对湍流-翼型前缘干涉噪声的降噪没有贡献;波浪形前缘可以显著地降低湍流-翼型干涉噪声的声压级,达到良好的降噪效果。

This paper investigates the aeroacoustic noise of airfoil with straight trailing edge, serrated trailing edge and wavy leading edge using the microphone array technique. The noise reduction effects of bionic trailing edge and leading edges were experimentally investigated in an anechoic room. A single-leg spiral microphone array was designed to locate the two-dimensional sound sources. The results show that the noise from trailing edge dominates the noise sources in free flow with low turbulence intensity. The serrated trailing edge can reduce trailing edge noise effectively within a broadband frequency region and the maximum noise reduction can be up to 10dB. Furthermore, the noise reduction effects of wavy leading edge depend on the wavy leading edge geometry. The noise reduction increases with decreasing wavelength of wavy leading edge. The results of turbulence-airfoil interaction noise show that, the turbulence-airfoil interaction noise is dominant around the airfoil leading edge. The wavy leading edge reduces the sound pressure level of turbulence-airfoil noise significantly. However, the serrated trailing edge leads to little contribution to the turbulence-airfoil interaction noise reduction.