Accession Number:

ADA581793

Title:

Elliptical Acoustic Particle Motion in Underwater Waveguides

Descriptive Note:

Final technical rept. 1 Jan 2008-31 Dec 2012

Corporate Author:

WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Personal Author(s):

Report Date:

2013-03-27

Pagination or Media Count:

27.0

Abstract:

The degree of circularity is a vector quantity relating to the acoustic particle motion induced in an acoustic field, and is formulated by measurements of the acoustic particle velocity or the complex vector intensity. It characterizes the ellipticity of the particle motion path that, for example, can arise when there is interference between a source signal and its reflections. In an ocean waveguide the spatial dependence of this vector property depends on the water column sound-speed, surface conditions and bottom properties, in addition to the sourcereceiver geometry. In waveguides with nearly horizontal boundaries, the vertical component of the instantaneous intensity can be used to provide an approximation to the degree of circularity. This approximation, applied to acoustic pressure measurements from two closely spaced hydrophones made in 2006 off the New Jersey coast in waters 80 m deep, is used to invert for environmental parameters of the sediment structure.

Subject Categories:

  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE