A NEW METHOD FOR PREDICTING THE SOUND-ABSORPTION OF PERFORATED ABSORBER SYSTEMS

A new theoretical model for predicting the sound absorption of perfora ted absorber systems is presented. The system with a perforated panel consists of an arbitrary combination of porous and air layers backed b y a hard wall, This model includes the effect of the diffraction pheno menon caused by impedance discontinuities of the boundary surface, whi ch has been disregarded in the past studies. Numerical results for ext ensive materials are compared with existing experimental data, which a re in fairly good agreement over the whole frequency range of practica l use. (C) 1997 Elsevier Science Ltd.