可渗透壁对翼型声涡相互作用下流场及声场的影响

由仿生学原理构建的可渗透翼型对湍流气动噪声抑制作用已展现良好的应用前景。对NACA 0012可渗透翼型和实体翼型进行了数值计算，得到了声涡相互作用下气动噪声声场和流场，分析了可渗透壁对翼型流场和声场的影响。研究表明，相对实体翼型，可渗透壁通过减小声源强度降低了主纯音噪声声压级幅值和远场总声压级，消除了高阶离散纯音，但对噪声的指向性没有较大改变。进一步的流场分析表明，可渗透壁对翼型气动性能影响不大的情况下能够降低边界层扰动和翼型后缘大尺度涡旋强度，并推迟分离泡转捩和再附位置。

Influence of permeable wall on flow field and sound field of airfoil acoustic vortex interaction

The permeable airfoil based on bionics has a good application prospect in suppression of turbulent aeroacoustic noise.Numerical calculation of NACA 0012 permeable and solid airfoil was carried out to obtain the aeroacoustic sound field and flow field under acoustic vortex interaction, and the effect of permeable wall on the flow field and sound field was analyzed.The results show that the permeable wall reduces the amplitudes of the sound pressure level of the main tonal noise and the total sound pressure level of the far field by decreasing the intensity of the sound source, and eliminates the discrete frequency tonal noise, but the noise directivity does not change significantly, compared with a solid airfoil.Further analysis of flow field shows that the permeable wall can reduce boundary layer disturbance and large-scale vortex strength at the trailing edge of the airfoil, and delay separation bubble transition and reattachment position under the condition that the influence of permeable wall on the aerodynamic performance of the airfoil is low.