摘要
受猫头鹰翅膀前缘锯齿和座头鲸鳍肢前缘凸起的启发,本文在NACA0018翼型的基础上,设计出单波长和双波长叠加前缘仿生结构,通过数值方法研究仿生翼型的噪声辐射特性。结果表明:在0°攻角均匀来流下,仿生翼型翼面上的压力脉动整体上有明显降低,幅值最大减小50 Pa,且主峰频率值发生频移,仿生翼型改变了原始翼型的流场和涡脱落结构;正弦波形前缘叶片声压级随着相对振幅h/C的增大而减小,随着相对波长λ/C的减小而减小;仿生结构可以抑制叶片窄带尖峰噪声,使翼型在整个频率范围内表现出宽频特性;低频下,仿生翼型声压级与原型相差最大,降噪效果最好,翼型声源为典型偶极子源噪声,其声学指向性呈“8”字状,该特征随声辐射的频率增大而消失。综合分析后,叠加波形前缘叶片F声学性能最佳。
Inspired by the serrated leading edge of the airfoil of the silent flying owl and the raised edges of humpback whale flippers,a single-wavelength and double-wavelength superimposed leading edge bionic structure was designed on the basis of NACA0018 airfoil.Under uniform flow at 0°angle of attack,the noise radiation sound field of the bionic airfoil was investigated by numerical method.The numerical results show that the pressure fluctuation near the wall of the bionic airfoil decreases obviously with max.reduction amplitude of 50 Pa,and the frequency shift of the main peak of the pressure fluctuation occurs,which indicates that the bionic airfoil has changed the flow field and the vortex shedding structure of the original airfoil.The sound pressure level of the airfoil with leading edge of sinusoidal waveform decreases with the increase of the relative amplitude h/C,and decreases with the decrease of the relative wavelengthλ/C;The bionic structure can suppress narrowband spike noise of the airfoil and make bionic airfoil show broadband characteristics in the whole frequency range;At low frequencies,the difference between the sound pressure level of the bionic airfoil and the original airfoil reaches maximum value,and the noise reduction effect is best.The sound source of the airfoil is a typical dipole source noise,and its acoustic directivity presents the shape of“8”.This feature gradually disappears as the frequency of acoustic radiation increases.After comprehensive analysis,the acoustic performance of the bionic airfoil F with double-wavelength superimposed leading edge is optimal.
作者
陈二云
邬长乐
杨爱玲
李国平
CHEN Eryun;WU Changle;YANG Ailing;LI Guoping(Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Ship Equipment Research Institute,Shanghai 200031,China)
出处
《流体机械》
CSCD
北大核心
2021年第7期20-28,共9页
Fluid Machinery
基金
国家自然科学基金项目(51106099)。
关键词
压力脉动
仿生翼型
宽频特性
声辐射
pressure pulsation
bionic airfoil
broadband characteristics
acoustic radiation
