NON-LINEAR EFFECTS IN A FOCUSED UNDERWATER ACOUSTIC SYSTEM.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1969
- Accession Number
- AD0707734
Entities
People
- Kenneth Frank Scigulinsky
Organizations
- Naval Postgraduate School