Statistical-Empirical Modelling of Airfoil Noise Subjected to Leading Edge Serrations

With the objective of reducing the broadband noise from the interaction of highly turbulent flow and airfoil leading edge, sinusoidal leading-edge serrations were investigated as an effective passive treatment. An extensive aeroacoustic study was performed to determine the main influences and interdependencies of factors, such as the Reynolds number, turbulence intensity, serration amplitude, and wavelength as well as the angle of attack on the noise-reduction capability. A statistical–empirical model was developed to predict the overall sound pressure level and noise reduction of a NACA 65(12)-10 airfoil with and without leading-edge serrations in the range of chord-based Reynolds numbers of 2.5×105≤Re≤6×105. The observed main influencing factors on the noise radiation were quantified in a systematic order for the first time. Moreover, significant interdependencies of the turbulence intensity and the serration wavelength, as well as the serration wavelength and the angle of attack, were observed, validat...