Passive, remote and omnidirectional suppression of sound source radiation via an acoustic superscatterer

Abstract

Effective direct control of the sound source is the fundamental solution to the problem of noise. Herein, we propose a passive, non-closed and remote scheme for omnidirectional reduction of the sound power radiated from vibrating sources. The physical mechanism of this scheme is to design an acoustic superscatterer based upon the idea of transformation media so that the virtual boundary of the acoustic superscatterer can overlap with the radiation boundary of the sound source to construct drastic multiple scattering effects. Through theoretical analyses and numerical simulations, we confirm the effectiveness of adopting an acoustic superscatterer to significantly suppress the sound radiation power generated by some typical dipolar sources in air. Our study shows that by arranging no more than two acoustic superscatterers at designated positions away from a dipolar thin rod, about 90% of the sound radiation power, i.e. 10 dB, can be suppressed in all directions of the dipole axis. This preliminary work could aid research into the use of passive methods to achieve non-contact omnidirectional noise control of vibrating sources.

A subwavelength ventilated structure for efficient broadband sound insulation

“…Based on the theory of slow waves, simple grating arrays are installed on the inner or outer walls of ducts [18,19]. In addition, in recent studies, Fano-like and Mie resonances have often been used for sound insulation [20], and the acoustic superscatterers can control the radiation of sound source directly by using transformation media method [21,22]. The HR has a strong resonance with a single peak, whereas the Fano-like resonance has serial resonant peaks for wave interference.…”