“During low-speed navigation, mechanical noise generated by power equipment operation constitutes the primary noise source for underwater vehicles, serving as their key acoustic signature for detection – typically manifested as a series of low-frequency tonal components,” the researchers said.
“Implementing vibration-damping measures to diminish energy transmission from engines through supporting structures is crucial for enhancing underwater vehicles’ acoustic stealth performance,” they added.
During testing, a scaled-down model with the new technology reduced noise levels by 24dB (12dB passive plus 12dB active) at 100 Hz and 26dB at 400 Hz.
According to the team, the system has an effective bandwidth of 10–500Hz. This, they explain, should cover most typical engine harmonics, while real-time noise cancellation was possible thanks to the system’s extremely short response time, according to the study.