Acoustic performance of micro-grooved elements

The transfer impedance and the absorption coefficient of MGEs and MPEs are measured, modelled and compared in this study. The acoustics of the micro-channels is treated in detail, the impedance end corrections are determined and the non-linear effects are accounted for. The linear behaviour of MGEs is described by extending the models for slit-shaped perforated elements. The quasi- and non-linear behaviours are expressed as a function of the Shear number and Strouhal number by curve fitting the experimental results.