Design and performance study of acoustic meta-liner under flow conditions

Abstract This paper studies the performance of acoustic Meta-Liners designed under flow conditions. Most current studies on acoustic Meta-Liners are conducted under static conditions, lacking designs directly targeting flow environments. Based on the typical acoustic metamaterial consisting of a perforated plate and a labyrinthine cavity, two subwavelength low-frequency acoustic Meta-Liner units (Structure 1 and Structure 2) operating at 380 Hz are designed under static and flow conditions, respectively. On this basis, two Meta-Liners (Liner 1 and Liner 2) are obtained. Theoretical calculations, numerical simulations, and experiments are used to investigate the acoustic characteristics of the Meta-Liner units and Meta-Liners. The results show that the sound absorption coefficients of the two Liner units are basically consistent under static conditions. However, under Mach numbers of 0.05, 0.1, and 0.15, compared with Liner 1 (Static-based design), the transmission loss of Liner 2 (Flow-based design) is increased by 260%, 243%, and 100%, respectively. This indicates that the Meta-Liner designed under flow conditions has a better noise reduction effect in the above flow environments. This study has broad application value for the application of acoustic Meta-Liners in aviation noise reduction.