Arbitrary shaped acoustic omnidirectional absorber based on transformation theory

Abstract

In this study, an arbitrary shaped acoustic omnidirectional absorber (AOA) is achieved for absorbing incoming acoustic/elastic waves in the ambient environment. Using the transformation acoustics theory, we present a theoretical framework for two-dimensional acoustic path guidance around arbitrary shapes for which the material parameters in the transformed space can be obtained analytically. Results indicate that the transformed space is distorted rather than compressed; numerical simulations confirm that these absorbers exhibit a remarkably large absorption and that the proposed method can control acoustic absorption for arbitrary geometries of interest. This method can potentially be applied to sound absorption and noise control.