Broadband noise prediction for aerofoils with a serrated trailing edge based on Amiet's theory

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.

Automated summary

This study examines the feasibility of using Amiet's theory to predict the noise reduction effect of serrated trailing edges, as well as improving prediction accuracy through directivity correction. Experimental results from wall-resolved large-eddy simulations show a significantly improved prediction with this correction method.