An Asymmetric Absorption and Reflection System Based on Mie Resonators

In this paper, an asymmetric system for effective acoustic absorption and reflection is constructed by attaching Mie resonators with varying channel widths to the pipeline walls. At operational frequencies, this system achieves coupling of acoustic bright and dark modes. The dark and bright mode resonators dissipate and reflect acoustic waves through strong dissipation and weak damping, respectively. Consequently, the dark mode side almost completely absorbs incoming acoustic waves, while the bright mode side nearly fully reflects them. Theoretical and numerical studies indicate that at the frequency near 246 Hz, there is a $90 \%$ absorption rate when acoustic waves enter from the left port, and a $64 \%$ reflection rate when entering from the right port. Additionally, by increasing the number of Mie resonators with a specific channel width, the system asymmetry is enhanced, and concurrently, the bandwidth of the reflection curve from the right port is also widened. This work provides an effective method for ventilated acoustic absorbers and acoustic wave modulation devices.