Numerical Study of In-Situ Acoustic Impedance and Reflection Coefficient Estimation of Locally Reacting Surfaces with Pressure-Velocity Probes

The characterization of the acoustic sound pressure and velocity field on the surface of absorbing materials plays a key role for the computation of their surface impedance and absorption coefficients. In this work, a technique based on the equivalent source method (ESM) is used to estimate the pressure and velocity field in order to compute the surface impedance and reflection coefficient of a locally reacting surface. The assessed in-situ technique only requires measuring on a single layer with an array of pressure-velocity (p-u) probes. A numerical simulation study is performed to compare the estimated values with those obtained using a double layer of pressure sensors. Results show a significant improvement in the lower frequency range in terms of both reconstruction accuracy and robustness against noise.