Dynamically adjustable directional acoustic radiation based on non-uniform cylindrical labyrinth structure

Abstract

In this work, a cylindrical four-channel non-uniform labyrinth structure is constructed. The ring shaped metamaterial designed by using the rotational anisotropy of the structure can control sound wave and achieve dynamically adjustable directional sound radiation. The cylindrical non-uniform labyrinth structure comprised of four channels has dipole resonance characteristic. At the dipole resonance frequency, sound waves can radiate from the openings of two sector channels that occupy a large proportion. At this time, the cylindrical non-uniform labyrinth structure can be approximately regarded as a dipole sound source. For the cylindrical uniform labyrinth structure, the sound transmission property will not change as it rotates around its center. However, when the cylindrical non-uniform labyrinth structure rotates around its own center, the position of the dipole sound source and the direction of the radiated sound wave also change. Placing a point sound source in the center of the circular metamaterial composed of 18 non-uniform labyrinth structures, and adjusting the rotation angle of the circular non-uniform labyrinth structure so that each structure lies in the conductive or cut-off state, the propagation of the point sound source in all directions can be controlled. The propagation characteristics of these structures are utilized to achieve dynamically adjustable directional sound radiation. In addition, the influence of the rotation angle of the cylindrical non-uniform labyrinth structure on the transmitted sound wave is studied, and the switching effect of the non-uniform cylindrical labyrinth structure in the constructed sound source system is explored, which provides a new idea for constructing simple directional radiation acoustic equipment.