Acta acustica united with acustica vol:89 issue:4 pages:595-603
An asymptotic expression for the monopole field reflected by non locally reacting porous layers has been obtained previously by Allard et al. . A simplified version similar to the one obtained by Chien and Soroka  can be used to measure the surface impedance of thin layers from pressure measurements around grazing incidence. Simulations and measurements are performed on a material of medium flow resistivity for two thicknesses and frequencies up to 5 kHz, to test the performances of the method under more general conditions.