Acoustic noise estimates for a quiet unmanned underwater vehicle.

Acoustical Technologies Inc. (ATI) has been tasked by a number of clients to predict the radiated noise of unmanned underwater vehicles (UUVs). Laboratory, dockside, and at sea measurements have been taken on 21‐in.‐diameter, 20‐ft‐long prototype vehicles. Data were obtained during operation of the propulsion motors, control surfaces, and other UUV components. Structural impact hammer testing was also used to estimate propagation path transfer functions. Acoustic noise and structural vibration sensors were recorded on the ATI multi‐channel data acquisition system and analyzed to produce narrow and broad bandwidth spectral estimates over the 10‐Hz–100‐KHz frequency range. Radiated noise predictions from the component source level data and transfer functions were made and illustrate the importance of selecting quiet components and appropriate noise control. This paper takes a look at how quiet a 21‐in.‐diameter 20‐ft‐long UUV could be using what is currently known about typical UUV component hardware. This is not an estimate for a real UUV but a radiated noise model based on an ATI concept using quiet components, practical noise control, and generic transfer functions. Radiated noise estimates will be presented at several operating speeds.