Full space destructive interference by acoustic-null medium

Abstract

Traditional destructive interference between two out-phase acoustic sources only occurs at certain spatial areas. We propose a method to achieve acoustic destructive interference in the whole space by setting two out-phase acoustic sources inside the acoustic-null medium (ANM). ANM is a highly anisotropic medium designed by transformation acoustics, whose function is to greatly compress its inner points along the main axis. We design an implementation model of ANM by filling hydrogen in brass slabs, which shows good full space destructive interference effect by numerical simulations. The proposed method will provide a new way to achieve sound suppression and noise reduction.