The Effect of Scattering and Absorption on Noise from a Cavitating Noise Source in the Subsurface Ocean Layer.

• Main Author: Tronstad,Yngvar Dag
• Other Authors: NAVAL POSTGRADUATE SCHOOL MONTEREY CA
• Format: Text
• Language: English
• Published: 1981
• Subjects: Torpedoes; Acoustics; *ACOUSTIC ABSORPTION; *ACOUSTIC SCATTERING; *UNDERWATER ACOUSTICS; *HOMING TORPEDOES; COASTAL REGIONS; OCEAN SURFACE; SURFACE ROUGHNESS; THESES; SHALLOW WATER; BUBBLES; SOUND TRANSMISSION; HETEROGENEITY; SEA STATES; SURFACE TARGETS; NORWEGIAN SEA; TORPEDO ATTACK; LOW FREQUENCY; SUBSURFACE; ABSORPTION COEFFICIENTS; TURNING(MANEUVERING); PASSIVE SONAR; CAVITATION NOISE; Square low detectors; Shadowing; Norwegian Sea
• Online Access: http://www.dtic.mil/docs/citations/ADA105758; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA105758

When investigating the detection performance of a passive homing torpedo used against shallow draft surface ships, certain environmental factors such as the rough sea surface and the bubble dominated inhomogeneous layer near the sea surface have to be considered. This thesis attempts to gain some insight into the behavior of a homing torpedo system during its critical attack phase, as well as getting some indications of the relative importance of the scattering mechanisms and the induced tactical limitations. An idealized propagation model was used as reference of comparison. For a given sea state and target speed the results stress the importance of low operating frequency as well as a high maximum turn rate. They also point to the importance of having a search depth below the bubble-dominated subsurface layer, and a variable speed capability during the torpedo's attack phase. (Author)