Ultra-broadband acoustic ventilation barrier based on multi-cavity resonators

The numerical simulations and experimental results of an ultra-broadband acoustic ventilation barrier composed of periodic unit cells are reported in this paper. Based on multiple mechanisms, including sound absorption by eigenmodes of the unit cell and sound reflection by a plate structure on upper surface of the unit cell, a single-layer ventilation barrier with broadband sound reduction is designed, and its working bandwidth can reach about 1560 Hz. The experimental results accord well with the simulation results. Furthermore, two types of three-layer ventilation barriers are designed and demonstrated by using the unit cells with different values of a (the length of the hollow square region) and w (the width of the channel between the adjacent cavities), and the bandwidths of both ventilation barriers can increase to 3160 Hz and 3230 Hz, respectively. The designed barrier structures have the advantages of ultra-broadband sound reduction and ventilation, which paves the way to designing high-performance ventilation barriers for the applications in environmental protection and architectural acoustics.