Engineering Solutions to Acoustic Problems

Airborne Noise Analysis


Results of Designer-NOISE™ compared
with measurement. (click to enlarge)

Airborne noise on vessels can come from many sources and paths, including noise and vibration from machinery, propeller and thruster induced vibrations, HVAC noise, 'wave slap' noise, and other sources that are specialized to certain operations such as aircraft and related equipment on an aircraft carrier. Determination of noise on vessels requires an intimate understanding of the mechanisms that generate noise as well as the interaction between the ship structure and the acoustical environment. NCE has predicted the noise in compartments and topside locations on hundreds of vessels, and has verified these predictions with measurements (See Measurement and Diagnostic Surveys)


NCE's Designer-NOISE™showing
model of Fisheries Research Vessel.
(click to enlarge)

 

NCE uses multiple tools to predict noise on vessels, including NCE's own Designer-NOISE™ prediction program. NCE also uses other methods to predict noise, ranging from standard "cookbook" methods such as the SNAME "Design Guide for Shipboard Airborne Noise Control" to detailed acoustical finite element models. NCE also keeps a complete database of machinery and vessel noise and vibration from past projects to assist with the design of new vessels. This complete tool set allows NCE to perform accurate noise predictions for any ship design, source, and noise path.


Diagram of three paths of noise
in any vessel. (click to enlarge)

 

Once a prediction has been performed, NCE can assist clients in identifying if a ship will meet its noise goals. These goals may be explicitly stated in the ship specification, but may also be ambiguous. NCE has vast experience working with clients to identify proper noise goals based on established standards (ABS, IMO, SNAME, etc.).

Furthermore, NCE can help to reduce noise in order to meet noise goals by identifying proper noise control treatments. While there are a myriad of possible treatments for noise (absorption, damping, etc.) knowing the best situation and location to use each treatment takes experience and knowledge. NCE's prediction tools allow for proper identification not only of the right treatment, but also of the right place to put that treatment. By doing this, noise goals can be met while minimizing impacts to non-acoustical factors such as weight, space, and cost.