Modélisation de l'impédance acoustique normale des structures à panneaux perforés

Abstract
Perforated facings are currently used in sound absorption applications. Different kinds of these facings are used in acoustical treatment of halls, in silencers and in aerial navigation. Our purpose is to study the acoustic impedance of these facings. One of the particular types of absorbing materials that will be considered in this paper consists of a porous homogenous blanket or an air layer placed in front of a hard wall and covered with a perforated facing. In another way, the air layer between the perforated facing and the wall may be divided into cells by means of partitions. Our study is based on Brillouin's theory relating to perforated facings and on works carried out by Morse and Ingard concerning porous material.The choosen model for simulating these different profiles has been verified practicaly using a Kundt tube.