Accession Number : AD0707734

Title :   NON-LINEAR EFFECTS IN A FOCUSED UNDERWATER ACOUSTIC SYSTEM.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF

Personal Author(s) : Scigulinsky,Kenneth Frank

Report Date : DEC 1969

Pagination or Media Count : 56

Abstract : A focused system having non-coincident foci was used to study the phenomenon of non-linear mixing in water. Primary frequencies of 343 kHz and 383 kHz provided a scattered difference frequency of 40 kHz. Enhancement of the difference frequency signal at incipient cavitation was verified. A delay between energization of the system and signal enhancement was linked to the state of non-linearity of the medium and provided strong evidence for the existance of a virtual source at 40 kHz. Directivity measurements of the focused system at 40 kHz revealed a multilobed structure, but the presence of pseudosound degraded the measurements and attempts to correlate the lobe structure with a particular virtual source configuration were unsuccessful. (Author)

Descriptors :   (*UNDERWATER SOUND GENERATORS, EXPERIMENTAL DATA), ACOUSTICS, SOUND, FOCUSING, CAVITATION, MATHEMATICAL ANALYSIS, TEST EQUIPMENT, ELECTROACOUSTIC TRANSDUCERS, TEST METHODS, THESES

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE