基于鸮翼特征的曲线形尾缘锯齿翼型气动噪声研究

STUDY ON AERODYNAMIC NOISE OFAIRFOILWITH CURVED SERRATION TRAILING EDGE BASED ON CHARACTERISTICS OF OWLWING

受到鸮类“静音飞行”的启发,将猫头鹰羽毛特有的曲线锯齿结构应用到三角形锯齿齿边,设计曲线形尾缘锯齿翼型,探究仿生锯齿结构的降噪潜力。以NACA0018翼型为原型翼型,通过大涡模拟(LES)与FW-H声类比方程相结合的方法,分析原型翼型、仿生曲线形锯齿尾缘翼型和传统三角形锯齿尾缘翼型的气动声学特性。结果表明,仿生曲线形锯齿尾缘翼型在声指向分布的所有方位角的总声压级均有降低,相比于传统的三角形锯齿尾缘翼型,噪声值最高能降低3.77 dB。压力脉动云图和流向速度的湍流波动分布结果表明,仿生曲线形锯齿可有效抑制尾缘附近的压力脉动,显著减小齿中部的湍流波动,从而降低翼型的气动噪声。

Inspired by the silent flight of owl,the special curved serration structure of the owl’s feather was applied to the edge of triangular serration,and an airfoil with curved serration trailing edge was designed.Meanwhile,the potential noise reduction effect of the bionic curved serration structure was investigated.The large eddy simulation(LES)and the FW-H acoustic analogy method were conducted to analyze the aeroacoustic characteristic between the NACA0018 prototype airfoil,the bionic curved serration airfoil and the triangular serration airfoil.The simulation results reveale that the overall sound pressure levels of the bionic curved serration airfoil decreases at all azimuth angles of the sound direction distribution.Compared with the traditional triangular serration airfoil,the maximum value of noise reduction of the bionic curved serration airfoil is 3.77 dB.The results of pressure pulsation cloud map and flow direction velocity turbulent wave distribution show that the bionic curved serration structure is beneficial to suppress the pressure fluctuation adjacent to the trailing edge and decrease the turbulent fluctuation at the middle region of the serration significantly,and thus reduce the aerodynamic noise of the airfoil with curved serration.