Underwater broadband sound insulation with chiral spiral structures

Low-frequency noise has been a long-standing issue in the context of a complex underwater environment. While theory related to low-frequency sound insulation in air has been developed, systematic research on underwater sound insulation has not yet been established. In our work, we used a chiral variable pitch spiral structure to study underwater low-frequency sound insulation and calculated the sound insulation effect using different parameters. Our results show that the fixed-pitch spiral structure has a better effect on underwater sound insulation and can achieve 3505 Hz–5355 Hz wide-band sound insulation. This spiral structure breaks through the limitation of appearance and can achieve sound insulation at the frequency of interest without changing the outer profile of the structure. Accordingly, it has potential in underwater low-frequency sound insulation applications.