Tunable microperforated panel acoustic absorbers with coupling effects

Design for highly effective acoustic absorber with broadband sound attenuation is challenging due to the typically large size or intricate internal structures involved. In this study, a tunable microperforated panel (MPP) acoustic absorber is proposed that leverages the coupling effects between its sub-components to achieve broadband sound absorption. The theoretical and numerical models are first presented to evaluate the acoustic properties of the coupled MPP absorbers. In addition, the theoretical and numerical analysis clarifies how coupling effects enhance the absorption troughs in the proposed absorber. Finally, the acoustic performance of the coupled absorber under flow effects is tested. It achieves an average transmission loss of 18.92 dB across the 200-1700 Hz frequency range under static conditions. When the flow speed increases to 30 m/s, the liner maintains an average transmission loss of 18.17 dB over the same bandwidth, representing only a 3.96% performance reduction. Results highlight the potential of our coupled MPP absorbers to advance acoustic meta-liner design.