Trailing-edge serrations are used as means to reduce aerofoil broadband self-noise in various industrial applications. However, a reliable prediction of the reduced noise level has not been established to date. In this paper, the authors suggest that Amiet’s theory can be used to accurately predict the sound radiated from serrated trailing edges. A plausible explanation as to how the classical theory, originally derived from non-serrated (straight) trailing edges, also works for the serrated trailing edges is provided. Besides, the authors propose a directivity correction to the Amiet’s original model to account for realistic aerofoil geometry. The directivity correction provides a significantly improved prediction of the noise level in the upstream and downstream directions for both serrated and baseline trailing edge cases. This study is based on wall-resolved large-eddy simulations of Joukowski aerofoils with multiple serration geometries and in different flow conditions.

在各种工业应用中，后缘锯齿被用作降低翼型宽带自噪声的手段。然而，迄今为止还没有建立对降低的噪声水平的可靠预测。在这篇论文中，作者建议可以使用 Amiet 的理论来准确预测从锯齿状后缘辐射的声音。提供了关于最初源自非锯齿状（直）后缘的经典理论如何也适用于锯齿状后缘的合理解释。此外，作者建议对 Amiet 的原始模型进行方向性校正，以解释真实的机翼几何形状。对于锯齿状和基线后缘情况，方向性校正提供了对上游和下游方向噪声水平的显着改进预测。