Measuring monopole and dipole polarizability of acoustic meta-atoms

TL;DR

This paper introduces an experimental method to measure the monopole and dipole polarizability of acoustic meta-atoms, accounting for real-world effects and uncertainties, and applies it to 3D-printed labyrinthine structures.

Contribution

The paper presents a novel experimental approach for extracting acoustic polarizability that includes second-order effects and material uncertainties, validated on complex meta-atom geometries.

Findings

Shorter path length structures match numerical polarizability results.

Longer path length structures exhibit significant damping due to viscous and thermal losses.

The method effectively captures real-world effects in acoustic meta-atom characterization.

Abstract

We present a method to extract monopole and dipole polarizability from experimental measurements of two-dimensional acoustic meta-atoms. In contrast to extraction from numerical results, this enables all second-order effects and uncertainties in material properties to be accounted for. We apply the technique to 3D-printed labyrinthine meta-atoms of a variety of geometries. We show that the polarizability of structures with shorter acoustic path length agrees well with numerical results. However, those with longer path lengths suffer strong additional damping, which we attribute to the strong viscous and thermal losses in narrow channels.