Acoustic metamaterial design for aeronautical purposes

Labyrinth-shape quarter wavelength tubes are numerically studied under plane wave excitation, with analytical comparison. These labyrinth resonators (LRs) are tuned at 60, 90 and 120 Hz, and their sound absorption response exhibits maximum peak at those frequencies with high fidelity and performance. These objects can absorb tonal sources at very low frequencies, with an incredibly competitive thickness, resulting in the possibility of considering them for the design of acoustic liners for an aerospace engine, but also for the automotive and naval industries. They are put together to form an acoustic metamaterial which exhibits multiple tonal peaks, demonstrating that the performance of each resonator is not affected by their coupling.