基于圆柱形非均匀迷宫结构的动态可调定向声辐射

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

构造了一种圆柱形四通道非均匀迷宫结构,利用该结构设计的圆环型超构材料能够实现动态可调的定向声辐射.所构造的圆柱形非均匀迷宫结构具有偶极子共振特性,在偶极子共振频率附近,声波能够从两个占比较大的扇形通道开口向外辐射,此时的圆柱形非均匀迷宫结构可近似地看作一个偶极子源.当圆柱形非均匀迷宫结构围绕圆心进行旋转时,所形成的偶极子源的位置和向外辐射声波的方向也随之发生改变.将点声源放置在由18个非均匀迷宫结构组成的圆环型超构材料的中心,调节圆柱形非均匀迷宫结构的旋转角度,使各微结构处于导通或截止状态,从而控制点声源在各个方向上的传播特性,实现具有动态可调特性的定向声辐射.此外,研究了圆柱形非均匀迷宫结构旋转角度对透射声波的影响,探究了微结构的开关效应,为构造简易的声定向辐射设备提供了新思路.

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.