Theoretical and numerical investigation of acoustic response of a multiperforated plate for combustor liner
Résumé
Multiperforated plates are used in combustion chambers for film cooling purpose. As the knowledge of the acoustic response of the chamber is essential for preventing combustion instabilities, the acoustic behaviour of the perforated plates has to be modeled. This can be done either by considering the transmission impedance of the plates, or their Rayleigh conductivity.
In this paper, the link between these two values is given in the frame of matched asymptotic expansions. Especially the far-field or near-field nature of the physical quantities used in the definition of the impedance and Rayleigh quantity is enlighted. Direct numerical simulations of the propagation of an acoustic plane wave through a perforated plate are performed and post-treated so that the assumptions underlying the definitions of impedance and Rayleigh conductivity are checked.