### 仿生学翼型尾缘锯齿降噪机理

1. 1. 西北工业大学 动力与能源学院, 西安 710129;
2. 中国空气动力研究与发展中心 空气动力学国家重点实验室, 绵阳 621000
• 收稿日期:2014-08-26 修回日期:2015-03-25 出版日期:2015-09-15 发布日期:2015-04-09
• 通讯作者: 乔渭阳 男, 博士, 教授, 博士生导师。主要研究方向: 叶轮机气体动力学, 航空发动机气动声学。 Tel: 029-88482195 E-mail: qiaowy@nwpu.edu.cn E-mail:qiaowy@nwpu.edu.cn
• 作者简介:仝帆 男, 博士研究生。主要研究方向: 叶轮机械气动声学。 Tel: 029-88482195 E-mail: nwputongfan@163.com
• 基金资助:

国家自然科学基金 (51276149);空气动力学国家重点实验室研究基金(SKLA20140201)

### Noise reduction mechanism of bionic airfoil trailing edge serrations

TONG Fan1, QIAO Weiyang1, WANG Liangfeng1, JI Liang1, WANG Xunnian2

1. 1. Schoole of Power and Energy, Northwestern Polytechnical University, Xi'an 710129, China;;
2. State Key Laboratory of Aerodynamics, China Aerodynamics Research and Development Center, Mianyang 621000, China
• Received:2014-08-26 Revised:2015-03-25 Online:2015-09-15 Published:2015-04-09
• Supported by:

National Natural Science Foundation of China (51276149); State Key Laboratory of Aerodynamics Research Fund (SKLA20140201)

Abstract:

Large eddy simulation and acoustic analogy are performed to investigate the effects of trailing edge serrations on airfoil self-noise. A SD2030 airfoil is used for study. The trailing edge serrations' amplitude is 10% of airfoil chord while the serrations' wavelength is 4% of airfoil chord. The fluid field of SD2030 airfoil at 0° angle of attack with incoming flow velocity of 31 m/s is simulated and the corresponding Reynolds number based on airfoil chord is about 310 000.The effect of trailing edge serrations on the turbulence flow field near the airfoil trailing edge is analyzed in detail. Then FW-H equation is used to calculate the sound field of the straight/serrated trailing edge airfoil with the help of the sound source information obtained by the large eddy simulation. It is found that trailing edge serrations can significantly reduce airfoil noise in low to middle frequency range. The noise reduction can reach up to 16 dB in narrow band in the frequency range smaller than 4 000 Hz. However, the airfoil aerodynamic performance is adversely affected by the trailing edge serration. Further results show that the airfoil noise is dominated by laminar boundary layer-vortex shedding noise under the current condition. It is found that the trailing edge serrations can suppress the laminar boundary layer-vortex shedding phenomenon and reduce the surface pressure fluctuation near the airfoil trailing edge as well as airfoil lift fluctuation. In addition, the turbulent fluctuation at low frequency and the vorticity near the trailing edge are reduced. The vortex spanwise correlation is also decreased near the trailing edge. These factors work jointly and lead to the final airfoil self-noise reduction.