Enhancing acoustic transmission in tri-branch structures via Green's function modulation

Abstract A novel three-branch acoustic structure is proposed to study the effects of branch and resonator length variation on sound transmission. The analytical expressions of acoustic reflection coefficient and transmission coefficient of structures are obtained by using the Green function method, which can be used to evaluate the acoustic performance of symmetric and asymmetric structures. The results show that increasing the resonator length isolates sound transmission in the target channel more effectively than adjusting the branch length, without interfering with transmission in other channels. Longer branches can increase the resonant frequency, thus achieving effective high-frequency control. Increasing the length of the resonator can reduce the resonant frequency of the natural mode, thus optimizing the low-frequency control. This study shows the critical role of structural size in sound control and contributes to the advancement of acoustic filters and devices that isolate potentially harmful frequencies.