Tuning the response of bubble-based metamaterials with short transient pulses

TL;DR

This paper investigates how short transient pulses can actively tune the acoustic response of bubble-based metamaterials, revealing new methods to control and optimize their behavior for various applications.

Contribution

It introduces a novel approach to actively control bubbly metamaterials' response using short transient pulses, supported by Fourier analysis and numerical simulations.

Findings

Bubbly meta-screens' response depends on incident wave characteristics.

Complex-frequency excitation causes energy storage in bubbles.

Active control of metamaterials can be achieved through pulse shaping.

Abstract

Bubble-based metamaterials have been extensively studied both theoretically and experimentally thanks to their simple geometry and their ability to manipulate acoustic waves. The latter is partly dependent on the structural characteristics of the metamaterial and partly dependent on the incident acoustic wave. Initially, the selection of specific structural characteristics is explained by presenting the Fourier transformations of the reflected waves for different arrangements of a bubbly meta-screen subject to Gaussian excitation. Next, our numerical study focuses on the changes induced to the response of a bubbly meta-screen, subject to different excitation pulses. For complex-frequency excitation the bubbles delay to return to their equilibrium position for a couple of moments, hence the energy is stored in the system during those moments. This research provides a new strategy to actively control the response of a bubbly meta-screen and seeks to inspire future studies towards further optimization of the incident pulse based on the functionalities in need.