Numerical prediction of absorbing materials via Computational AeroAcoustics

Marie Escouflaire , Stéphane Redonnet

In the context of reduction of the propulsive noise of airplanes, manufacturers are led to generalize the employment of “sound absorbing materials” (or “liners”), and to optimize their use. The aim of the present study is to improve the numerical prediction of noise attenuation by accurately modelling such absorbing materials either for time domain approaches (such as Computational AeroAcoustics) or for frequency domain methods (such as Boundary Element Method). Such a modelling raises several key questions, which are related to various aspects such as the type of flow involved (heterogeneities, turbulent boundary layers, etc.), the sound levels considered (non-linear phenomena), the diffraction effects induced by ruptures of impedance, etc. Besides specific theoretical developments dedicated to the accurate modelling of acoustic liners, the present work relies on specific calculations, to be compared against other results (analytical, numerical, and/or experimental). Therefore, a numerical campaign has been recently initiated, which aim is to numerically duplicate several canonical tests of noise absorption by acoustic liners. These cases will be used as means of validation to improve the consideration of an accurate acoustic impedance boundary condition for Onera's time and frequency domains solvers.

Mots clés: Aeroacoustics; Liners; Numerical Methods; Absorbing Materials

Domaines: Acoustique [physics.class-ph]

Marie Escouflaire, Stéphane Redonnet. Numerical prediction of absorbing materials via Computational AeroAcoustics. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810752⟩