Nonlinear Acoustics: Long Range Underwater Propagation, Air-Filled Porous Materials, and Noncollinear Interaction in a Waveguide.
Abstract
Research on three topics in nonlinear acoustics is described. (1) Nonlinear effects in long range underwater propagation. The equations of nonlinear geometrical acoustics have been derived from the general equations of fluid mechanics for and inhomogeneous fluid. And analytical solution for the waveform of an arbitrary pressure signal traveling along a ray path has been implemented by a computer program. Not included in the program are effects of reflection and focusing. (2) Nonlinear effects in air-filled bulk porous materials. Theory and experiments on the propagation of intense airborne sound in bulk porous materials are described. The primary source of nonlinearity is the velocity dependent resistivity of the materials. (3) Nonlinear interaction in rectangular waveguide. Two problems are considered, (a) distortion of a wave launched as a single tone in the 1,0 mode of the waveguide, and (b) noncollinear interaction of two noncollinear tones, one a low frequency wave in the 0,0 mode, the other a high frequency wave in the 1,0 mode. Keywords include: Nonlinear acoustics; Long range propagation; Inhomogeneous fluid; Porous materials (air-filled); Waveform distortion; Rectangular waveguide; Noncollinear interaction; and Coefficient of nonlinearity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 28, 1985
- Accession Number
- ADA161037
Entities
People
- David T. Blackstock
Organizations
- University of Texas at Austin