Investigation into the application of an acoustic metamaterial for sound attenuation with airflow

This paper presents a practical investigation into the development and potential noise control application of an acoustic metamaterial. Acoustic Metamaterials are capable of changing the natural properties of sound, giving exposure to a new range of acoustical phenomena that have never been witnessed before, such as a negative bulk modulus and a negative mass density. The material investigated consisted of a panel structure of concatenated Helmholtz resonators with diffraction characteristics, which was incorporated into an acoustic enclosure. The design aimed to attenuate sound across a wide frequency range, while allowing air to flow through the panel. Sound insertion loss tests of the enclosure were carried out in an anechoic chamber. Airflow resistance tests were also undertaken in a controlled environment. Satisfactory sound attenuation and air flow resistance results indicated this metamaterial has the potential to be used as a noise control solution for acoustic enclosures requiring ventilatio