Acoustic Analysis for a Moving Source with Application to an Isospeed Ocean
Abstract
Using ray theory, a general analysis is presented for the treatment of the effects of sound-source motion on the total acoustic field at a fixed receiving point. Sound speed is depth-dependent and the cw source follows an arbitrary path with arbitrary velocity. The received signal is interpreted as a waveform of arbitrary frequency whose amplitude and phase are time-dependent. Application of the theory is made to a constant sound-speed channel in which the source follows a short straight-line path with constant speed, and a linearized acoustic model is developed. Both primary and cumulative acoustic phase are examined as functions of time for various source-trajectory direction. An averaged Doppler-shift frequency, as well as unaveraged source frequency, is considered. Maximum phase change occurs for radial source motion and minimum change occurs for circumferential motion. Finally, acoustic phase is investigated when the source follows a long straight-line path. An approximate formula is derived for cumulative phase, which is found to be a hyperbolic function of time.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1975
- Accession Number
- ADA016967
Entities
People
- G. M. Jacyna
- J. G. Clark
- M. J. Jacobson
Organizations
- Rensselaer Polytechnic Institute