Underwater acoustic beam dynamics

• Published in: The Journal of the Acoustical Society of America 2009-07, Vol.126 (1), p.80-91
• Main Authors: Beron-Vera, Francisco J., Brown, Michael G.
• Format: Article
• Language: English
• Subjects: Acoustics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Physics; Underwater sound
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.3139901

Ray- and mode-based theoretical predictions of the spreads of directionally narrow beams are presented and compared to parabolic-equation-based simulations in deep-ocean environments. Both the spatial and temporal spreads of beams are considered. The environments considered consist of a range-independent deep-ocean background sound channel on which a highly structured sound-speed perturbation, associated with either internal waves or homogeneous isotropic single-scale turbulence, is superimposed. The simulation results are shown to be in good agreement with simple theoretical expressions which predict that beam spreading, in both the unperturbed and perturbed environments, is largely controlled by a property of the background sound channel-the ray-based stability parameter α or the asymptotically equivalent mode-based waveguide invariant β . These results are consistent with earlier results showing that wavefield structure and stability are largely controlled by α (or β ).