Aerofoil self-noise radiations subjected to serration flap angles
Aerofoil self-noise radiations subjected to serration flap angles
复制标题
受锯齿状襟翼角度影响的机翼自噪声辐射
DOI：
10.1007/s00348-021-03239-y
复制
发表时间：
2021
影响因子：
2.4
通讯作者：
Woodhead P
中科院分区：
文献类型：
--
作者：
Woodhead P
本文除了研究非对称翼型在锯齿后缘襟翼角从负（向下襟翼）到正（向上襟翼）变化时的气动声学响应外，还对锯齿后缘宽频带降噪的物理机制提供了一个新的视角。叶片载荷效应是直/非锯齿后缘平板的长度和襟翼角的函数，它在自噪声辐射中起着相当大的作用，而这一点迄今为止还没有得到很好的认识。当同一后缘平板被切割成双锯齿形时，锯齿效应（占主导地位）和叶片加载效应将同时支持自噪声降低。结果表明，锯齿形翼型的远场辐射可以通过襟翼角的方向进行有效的控制。在襟翼向下配置中，叶片负载将成为导致整个频率范围内的降噪性能劣化的负因素。在上翻式配置中，可以定义三个频谱频率区域。在低频区，锯齿间隙处的横流减弱将阻碍降噪能力。在中心频率区，湍流源的重新分布和湍流展向长度尺度的减小将增强降噪性能。在高频区，由于横向流动和湍流结构之间没有相互作用，也可以实现噪声性能的改善。一个新的概念，积极地证明了变化的锯齿襟翼角作为一个周期性的函数横跨展向方向（展向波形锯齿）。与无襟翼锯齿后缘相比，展向波形锯齿可以进一步提高中心和高频区域之间的降噪水平。图形摘要
AbstractBesides the investigation of the aeroacoustics responses of an asymmetric aerofoil subjected to serrated trailing edge flap angles from negative (flap-down) to positive (flap-up), this paper also provides a new perspective on the physical mechanisms of broadband noise reduction by a serrated trailing edge. The blade-loading effect, which is a function of the length and flap angle for a straight/non-serrated trailing edge flat plate, plays a considerable role in the self-noise radiation that is hitherto less recognised. When the same trailing edge flat plate is cut into a sawtooth serration shape, the self-noise reduction will be underpinned simultaneously by both the serration effect (dominant) and the blade-loading effect. The results demonstrate that the far-field radiation of a serrated aerofoil can be manipulated significantly depending on the direction of the flap angle. In the flap-down configuration, the blade-loading will become a negative factor that causes a deterioration of the noise reduction performance across the entire frequency range. In the flap-up configuration, three spectral frequencies zones can be defined. At the low-frequency zone, the diminished cross-flow at the sawtooth gaps will impede the noise reduction capability. At the central-frequency zone, the re-distribution of the turbulence sources and reduction in the turbulence spanwise length scales will enhance the noise reduction performance. Improvement in the noise performance can also be achieved at the high-frequency zone owing to the lack of interaction between the cross-flow and sawtooth structure. A new concept is positively demonstrated by varying the serration flap angle as a periodic function across the spanwise direction (spanwise wavy serration). When compared to a non-flap serrated trailing edge, the spanwise wavy serration is found to further increase the noise reduction level between the central and high-frequency regions.Graphic abstract
受控扩散翼型后缘噪声的几种噪声控制
影响因子：
1
作者：
S. Moreau;P. Laffay;A. Idier;N. Atalla
通讯作者：
N. Atalla
风力涡轮机应用翼型件的风洞测试
DOI：
--
发表时间：
2015
期刊：
影响因子：
--
作者：
M. Kuester;K. Brown;T. Meyers;N. Intaratep;Aurélien Borgoltz;W. Devenport
通讯作者：
W. Devenport
影响因子：
3.7
作者：
L. E. Jones;R. Sandberg
通讯作者：
L. E. Jones;R. Sandberg