Far-Term Noise Reduction Roadmap for the Midfuselage Nacelle Subsonic Transport

Abstract

A noise reduction technology roadmap study is presented to determine the feasibility for the midfuselage nacelle (MFN) aircraft concept to achieve the noise goal set by NASA for the far-term timeframe, which is beyond 2035. The study starts with updating the noise prediction of the MFN configuration modeled for the timeframe between 2025 and 2035, with a prediction of 34.3 dB cumulative effective perceived noise level below the stage 4 regulation. A suite of technologies that are deemed feasible to mature for practical implementation in the far term and for which the potentials for noise reduction have been demonstrated is selected for analysis. For each technology, component noise reduction is modeled either by available experimental data or by physics-based modeling with aircraft system-level methods. The noise reduction is then applied to the corresponding component predicted by advanced aircraft noise prediction tools. It is shown that the far-term MFN aircraft has the potential to achieve a cumulative effective perceived noise level up to 40.2 dB below stage 4 if all noise reductions are fully realizable. The key technologies to achieve this low noise level are assessed by the impact of each technology on the aircraft system noise.