Numerical and Experimental Investigation of a Phase Gradient Metasurface Lining

Abstract

This work presents an experimental and numerical study of a non-homogeneous acoustic treatment based on spacecoiling unit cells. A modular phase gradient metasurface is used in the experimental analysis as a wall lining in a Grazing Impedance Tube. A metacontinuum reduced order model of the cells is used in FEM simulations to predict the experimental results. The experiments and the numerical analysis show a good agreement in terms of the predicted transmission coefficient spectrum for the selected benchmark problem. Although not optimized, the non-homogeneous acoustic treatment showed remarkable transmission loss in a wide range of frequencies, which can be explained by a subwavelength distribution of acoustic resonators with different resonance frequencies.