Underwater stealth metasurfaces composed of split-orifice-conduit hybrid resonators

The development of sound-absorbing materials for noise reduction in daily life has been a prolonged issue that also applies to a recognized need for submarine anechoic tiles to stay independent from SONAR (SOund NAvigation Ranging). Here, we present an underwater stealth metasurface that uses split-orifice-conduit (SOC) hybrid resonators to significantly reduce its acoustic reflectance. A theoretical analysis of SOC elements provides an approach to quantifying acoustic characteristics using the transfer matrix method in a single metasurface. The findings confirm that we can tune the absorption with respect to a resonating frequency by adjusting geometrical parameters. Utilizing a hybrid mechanism that enables easy access to coupled resonances, we obtain broadband absorption spectra even in the presence of a covariant sound speed profile in the deep sea and a thermoviscous effect on unit cells of the metasurface. Such a metasurface will provide a further step toward developing feasible underwater stealth technologies for submarines and remains to be experimentally demonstrated.

Automated summary

This study presents an underwater stealth metasurface using split-orifice-conduit (SOC) hybrid resonators to reduce acoustic reflectance significantly. The research provides a theoretical analysis of SOC elements and demonstrates the possibility of tuning absorption with respect to resonating frequency by adjusting geometrical parameters. The hybrid mechanism enables access to coupled resonances, leading to broadband absorption even in challenging underwater conditions, making it a promising development for underwater stealth technologies.