The noise generated by finite, wall-mounted airfoils strongly affects the total noise from aerodynamic applications such as small unmanned aerial vehicles, micro wind turbines and cooling fans. In an attempt to understand the effect of airfoil thickness on the trailing edge tonal noise generated by such airfoils, detailed wind tunnel experiments have been performed on two symmetric NACA-type airfoils with aspect ratio of 1.2 and nominal thicknesses of 12% and 18% of the chord length. The measurements included microphone array measurements, hot-wire measurements in the near wake of the airfoils and surface flow visualizations. It was found that the thickness has a strong impact on the tonal noise generation. At non-lifting conditions, the thinner airfoil generates tonal noise, while the thicker airfoil radiates broadband noise. At a slightly higher angle of attack ($6^{\circ }$), both airfoils generate tonal noise, but with different frequency and side-tone characteristics. Further increasing the angle (to ${12}^{\circ }$) resulted in the generation of tonal noise from the thicker airfoil, while the far field spectrum obtained for the thinner airfoil has broadband character. This is attributed to the tip flow having stronger influence over the airfoil span in the case of the thinner airfoil leading to suppression of the tonal noise mechanism. Maps of the sound source locations, flow visualizations as well as detailed hot-wire measurements also provide further insight into the sound source mechanisms.

有限的壁挂式机翼产生的噪声会严重影响空气动力学应用的总噪声，例如小型无人机，微型风力涡轮机和冷却风扇。为了了解机翼厚度对此类机翼产生的后缘音调噪声的影响，已对两个对称的NACA型机翼进行了详细的风洞实验，宽高比为1.2，标称厚度为12％和18％和弦长度。这些测量包括传声器阵列测量，机翼接近尾声时的热线测量以及表面流可视化。已经发现，厚度对音调噪声的产生有很大的影响。在非举升条件下，较薄的机翼会产生音调噪声，而较厚的机翼会辐射宽带噪声。$6^{\circ }$），两个机翼都会产生音调噪声，但具有不同的频率和侧音特性。进一步增加角度${12}^{\circ }$）导致较厚的机翼产生音调噪声，而较薄的机翼获得的远场频谱具有宽带特性。这归因于在较薄的翼型的情况下叶尖流动对翼型跨度具有更强的影响，从而抑制了音调噪声机制。声源位置的地图，流动可视化以及详细的热线测量也可以进一步了解声源机制。