Work

Active control of high-level tonal noise in flows up to Mach 0.5 using Harmonic Acoustic Pneumatic Sources

Year: 2026

Type: article

Abstract: The Harmonic Acoustic Pneumatic Source (HAPS) has been designed to act as a secondary source for active control of fan noise in aircraft engines, taking advantage of the pneumatic energy from the turbofan. One challenge for its use in the nacelle is that the source has to produce a high-level tonal noise while being subjected to a significant grazing flow. The objective of this paper is to experimentally demonstrate active control of high-level multimodal tonal noise using HAPS installed on an aeroacoustic bench which reproduces the flow conditions encountered in a nacelle. A model of the acoustic radiation of the HAPS in a flow duct is also proposed, representing it as a point source with a specified acoustic mass flow rate. The experimental results indicate that HAPS can control the amplitude, phase and frequency of a high-level tonal anti-noise (120–145 dB), even with flow velocities up to a Mach number of 0.5. Attenuations between 9 dB and 30 dB are achieved for multimodal primary tonal noise between 400 Hz and 1160 Hz, with up to 3 propagating modes, showing the effectiveness of HAPS as secondary sources under these conditions.

Source: Acta Acustica

DOI: 10.1051/aacus/2026078

Authors: Alexandre Schiavini, Philippe Micheau, Gwénaël Gabard, Thomas Humbert, Pierre Grandjean