Perfect broadband sound absorber metamaterial for noise reduction in a rocket launch

Abstract

Metamaterials based on Helmholtz resonators represent alternatives for noise mitigation applications where traditional materials can not be used due to the environmental conditions. One such case is found in the extreme acoustic event caused by a rocket launch. Metamaterials can also be designed on demand to act on the sound waves at a specific frequency range, which depends on the particular application. In this work we present the design procedure of a metamaterial panel, with a potential use for noise mitigation during a rocket launch. The proposed sound absorber presents almost perfect sound absorption in a prescribed bandwidth. The geometrical parameters of a unit cell, the building block of the panel, are obtained by using the transfer matrix method, and the use of optimization algorithms. The effective acoustical parameters of the designed metamaterial are also obtained. Using the effective parameters, the acoustical response of a panel built from an array including a large number of unit cells is numerically computed. Finally, experiments in an impedance tube that validate the theoretical results are presented.

@inproceedings{RequenaINTERNOISE2021a,
 author = {José Manuel Requena-Plens and Rubén Picó and Victor J. Sánchez-Morcillo and Noé Jiménez and Alejandro Cebrecos and Mara Escartí-Guillem},
 booktitle = {EuroNoise 2021: European Congress and Exposition on Noise Control Engineering. Madeira, Portugal. 24-27 October},
 doi = {http://www.sea-acustica.es/},
 editor = {Conference proceedings},
 month = {10},
 organization = {Sociedade Portuguesa de Acústica},
 pages = {1392-1400},
 series = {Oral},
 title = {Perfect broadband sound absorber metamaterial for noise reduction in a rocket launch},
 url = {http://www.sea-acustica.es/},
 year = {2021}
}