Numerical Simulations for Investigating Noise Transmission in Naval Vessels

Published in: Webinar on ‘Management of Structure Borne Noise’ INS Shivaji, 21st Nov 2020.

Author: Sharad Dhavalikar, Akula Chaturvedi, Ram Kumar Joga.

Date of Publication: November 2020

Underwater radiated noise (URN) signature is one of the most important stealth aspects of naval vessels. The limiting criteria of URN may vary from vessel to vessel depending upon the intended operations and operational regimes of the naval vessel. On-board noise plays important role in day to day activities and the comfort level of crew on-board the vessel. On-board noise criteria are generally in-line with IMO regulations irrespective of the ship type and operations. The critical noise sources as well as noise propagation for URN and On-board noise vary considerably. However, noise transmission is mainly categorized into the air-borne and structure-borne path. Prediction of noise and limiting excessive noise can be dealt at the design phase of the vessel with numerical aids. The prediction methods deal with air borne noise (ABN) and structure borne noise (SBN) separately. ABN radiated by sources is transmitted not only though open spaces but also through the bulkheads, decks, etc. and is received at various compartments, deck levels as on-board noise. On the other hand, SBN is the one due to acoustic vibrations of the structure. Both ABN and SBN transfer through the water as well at a distance far away from the vessel revealing specific URN signature of the vessel. This paper deals with various numerical techniques to predict noise transmission and to arrive at the design solutions in the initial design phase.