Experimental Estimation of the Frequency-Dependent Reflection Coefficient of a Sound-Absorbing Material at Oblique Incidence

Abstract

A method for experimentally determining the frequency-dependent reflection coefficient of a sound-absorbing material at oblique incidence is presented. The M-sequence method and a monopole source are used to measure pulse responses of melamine foam for different angles of incidence of an acoustic wave. Frequency dependencies of the reflection coefficient obtained at different angles of incidence are compared with that calculated theoretically using the Biot model and approximate inversion of the Fourier–Bessel integral.