Influence of internal wave fluctuations on acoustic underwater propagation

• Published in: The Journal of the Acoustical Society of America 2005-04, Vol.117 (4_Supplement), p.2548-2548
• Main Authors: Andreeva, Tatiana A., Durgin, William W., Wojcik, Stefanie E.
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4788473

The work presents a ray acoustic based analysis of the effect of ocean internal waves and its fluctuations on acoustic wave propagation. In the present work, it is shown that consideration of only perfect internal waves simplifies the real problem, disregarding the fluctuations of internal waves. The focus of the paper is to study numerically the influence of internal wave fluctuations and the role of an initial ray angle onto underwater acoustic propagation. In the present formulation the eikonal equation is considered in the form of a second order, nonlinear ordinary differential equation with harmonic excitation due to internal wave. The harmonic excitation is taken imperfect, i.e., with a random phase modulation due to Gaussian white noise. The amplitude and wavelength of the acoustic waves are used as the principle signal characteristics in bifurcation analysis. The regions of instability are identified using the bifurcation and phase diagrams. The effect of internal waves phase modulation is demonstrated by means of comparison of the numerical data obtained in the present work with data, obtained perfect internal wave. The preliminary analysis shows very strong dependence of acoustic propagation on intensity of fluctuations.