Sound absorption performance of lattice structures in spiral-shaped flow channels

This study investigates how incorporating a twisted wall structure into a lattice structure improves sound absorption performance based on the numerical and experimental investigation. The twisted wall structure is expected to lengthen the flow path of sound waves inside the sound-absorbing structure. In this study, finite element simulations have been conducted to compare the sound absorption characteristics at twisted angles of 0 deg, 180 deg and 360 deg. Note that the direct and homogenization methods are also applied in the simulations, and sound absorption measurements were also performed to confirm the same trends as the numerical and experimental results. As a result, an increase in the peak sound absorption coefficient and an improvement in the sound absorption coefficient at low frequencies were confirmed as the torsional angle increases. Furthermore, by calculating the flow length passing inside the sound-absorbing structure, the frequency at the peak sound absorption coefficient can be predicted.