12. Aeroacoustics Effects of the Wavy Leading Edge on a Fan-Rig SDT Stators

The interaction between the turbulent wake of the rotor and the stator vanes has been identified as one of the broadband noise main sources in a turbofan engine, in addition to the tonal noise. Studies inspired by the owl’s silent flight have shown that the application of certain natural properties of its wings, such as the serrated pattern on the leading edge (Wavy Leading Edge), are effective for reducing aircraft noise. The objective of this work is to analyze it on the stator vanes source diagnostic test (SDT) low-noise model of the EESC/USP rig-fan bench. The geometry of the new vanes was defined and printed for the experimental tests and the analysis of noise emissions. The bench has acoustic instrumentation for data acquisition, and for its spectral analysis, the Welch method is used in signal processing. Tests were carried out with fan rotation speeds from 800 to 1800 rpm for both stators. The acoustic measurements of the WLE stator showed a reduction of 1.5–4 dB in low and medium frequencies in broadband noise, while there was an increase at high frequencies of up to 1.2 dB. From this study, it is understood that there is no ideal serration that reduces noise for all types of conditions that are imposed; nevertheless, it is more efficient at low rotation speeds, which could be used to improve the aircraft landing or takeoff conditions.