Accession Number:

ADA182518

Title:

Problems in Nonlinear Acoustics: Parametric Receiving Arrays, Focused Finite Amplitude Sound, & Noncollinear Tone-Noise Interactions

Descriptive Note:

Annual summary rept. no. 2, 1 May 1986-1 Jul 1987

Corporate Author:

TEXAS UNIV AT AUSTIN DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

Report Date:

1987-07-01

Pagination or Media Count:

33.0

Abstract:

Three projects are discussed in this report. 1 Parametric Receiving Arrays. This project is a theoretical investigation into the use of a parametric receiving array for directive measurements of noise radiated by ships in reverberant environments. The analysis is based on a Gaussian beam model that takes nearfield diffraction into account. The scattering of sound is also investigated. 2 Focused Finite Amplitude Sound. A numerical solution is used to investigate the combined effects of nonlinearity, diffraction, and absorption on sound that propagates through a focal region. The analysis yields time waveforms, axial propagation curves, spectral power distributions, and beams patterns. 3 Noncollinear Tone-Noise Interactions. The noncollinear interaction of a pure tone and a band of noise that propagate in different modes of a rectangular duct is investigated both experimentally and theoretically. Keywords Nonlinear acoustics Parametric array Scattering of sound by sound Focused sound Waveguide Noise.

Subject Categories:

  • Acoustic Detection and Detectors
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE