Étude et caractérisation des solutions acoustiques pour un rotor caréné d’hélicoptère sous excitations réalistes

Abstract

This thesis presents the development of an analytical model for predicting the acoustic behavior of multilayer resonant structures used for noise reduction in aeronautical applications. The main objective is to provide a generic and reliable tool capable of modeling complex acoustic absorbers composed of multiple perforated plates and cavities, under realistic excitation conditions. The model is based on a transfer matrix approach that relates the acoustic pressure and volume velocity at the interfaces of each sub-element. This modular formulation allows different types of layers and geometries to be combined within a single framework while maintaining an accurate description of the local acoustic field. The approach also makes it possible to compare several material configurations within the same model, which facilitates parametric studies and optimization. Special attention is given to the inclusion of nonlinear effects that appear under realistic excitation. The model accounts for high sound pressure levels, which modify the resistance and reactance of perforated plates, as well as grazing flow effects along their surfaces. These contributions are handled through an iterative procedure that couples the local particle velocities and the effective surface impedance, ensuring consistency of the results in nonlinear conditions. The resulting analytical code provides an efficient and predictive tool for the analysis and design of multilayer acoustic treatments. It contributes to a better understanding of absorption mechanisms in realistic configurations and supports the development of more effective noise control solutions for advanced aeroacoustic systems.

Date	28 Apr 2026
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Thomas Dupont (Supervisor) & Maël Lopez (Co-supervisor)