The Silent Service

HONGMIN PARK – hongmini0202@snu.ac.kr

Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea, Seoul, Seoul, 08826, South Korea

WOOJAE SEONG
Professor of Seoul National University
http://uwal.snu.ac.kr

Popular version of 2aEA9 – A study of the application of global optimization for the arrangement of absorbing materials in multi-layered absorptive fluid silencer
Presented at the 187th ASA Meeting
Read the abstract at https://eppro01.ativ.me//web/index.php?page=Session&project=ASAFALL24&id=3771466

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–


Underwater Radiated Noise (URN) generated by naval vessels is critically important as it directly impacts survivability. Underwater Radiated Noise (URN) refers to the sound emitted by objects, like ships or submarines, into the water. This noise is generated by various sources, including the vessel’s machinery, propellers, and movement through water. It can be detected underwater, affecting their ability to remain undetected. So various studies have been conducted to reduce URN for submarines to maintain stealth and silence.

This study focuses on the ‘absorptive fluid silencer’ installed in piping to reduce noise from the complex machinery system. An absorptive fluid silencer is similar to a car muffler, reducing noise by placing sound-absorbing materials inside.

We measured how well the silencer reduced noise by comparing sound levels at the beginning and end of the silencer. Polyurethane, a porous elastic material, was used as the internal sound-absorbing material, and five types of absorbent materials suitable for actual manufacturing were selected. By applying a ‘global optimization method,’ we designed a high-performance ‘fluid silencer.’.

The above graph shows a partial analysis result, It can be observed that using composite absorbing materials provides superior sound absorption performance compared to using a single absorbing material.