- Volume 34 Issue 6
A heuristic method treating a layered ocean bottom in a ray modeling is to use the plane wave reflection coefficient for multiple-layered structure, named an one-layer assumption in this paper. We examine the validity of one-layer assumption in the case of two-layered ocean bottom, and obtain a simple inequality condition depending on the sound speed ratio, the ratio of layer thickness to source-receiver range, and the grazing angle of first reflected ray. From this inequality condition, it is shown that an one-layer assumption can be applicable to ray propagation problems at mid frequencies. Finally, numerical experiments are performed in the ocean environment similar to the East Sea in Korea. Incoherent transmission loss is calculated by the geometrical beam model with the plane wave reflection coefficient for multiple-layered ocean bottom and compared with the result of SNUPE 2.0, which is a parabolic equation package developed in Seoul National University.
Geometrical beam;Ray model;Plane wave reflection coefficient;Two-layered ocean bottom;One-layer assumption
- F. B. Jensen, M. B. Porter, W. A. Kuperman, and H. Schdmidt, Computational Ocean Acoustics, 2nd Edition (Springer, New York, 2011), pp. 188-189.
- C. Park, Y. Cho, J. Ahn, and W. Seong, "A study on the ray based broad band modeling for shallow water acoustic wave propagations" (in Korean), J. Acoust. Soc. Kr. 25, 298-304 (2006).
- E. K. Westwood and P. J. Vidmar, "Eigenray finding and time series simulation in a layered-bottom ocean," J. Acoust. Soc. Am. 81, 912-924 (1987). https://doi.org/10.1121/1.394571
- C. Park, W. Seong, P. Gerstoft, and M. Siderius, "Timedomain geoacoustic inversion of high-frequency chirp signal from a simple towed system," IEEE J. Oceanic Eng. 28, 468-478 (2003). https://doi.org/10.1109/JOE.2003.816684
- J. Dettmer, S. E. Dosso, and C. W. Holland, "Joint time/frequency-domain inversion of reflection data for seabed geoacoustic profiles and uncertainties," J. Acoust. Soc. Am. 123, 1306-1317 (2008). https://doi.org/10.1121/1.2832619
- L. M. Brekhovskikh and R. T. Beyer, Waves in Layered Media, 2nd Edition (Academic Press, New York, 1980), pp. 225-276.
- Jee Woong Choi, "Interpretation of ground wave using ray method in Pekeris waveguide" (in Korean), J. Acoust. Soc. Kr. 28, 208-212 (2009).
- J. M. Hovem, "Ray trace modeling of underwater sound propagation," in Modeling and Measurement Methods for Acoustic Waves and for Acoustic Microdevices, edited by M. G. Beghi (InTech, Rijeka, 2013).
- H. Medwin and C. S. Clay, Fundamentals of Acoustical Oceanography (Academic Press, San Diego, 1998), pp. 28-30.
- K. Lee and W. Seong, "Hybrid algorithm of the depth solver for wavenumber integration technique in an ocean waveguide with a porous bottom," J. Comp. Acous. 16, 71-82 (2008). https://doi.org/10.1142/S0218396X08003439
- K. Lee, "2D two-way parabolic equation algorithm using successive single scattering approach" (in Korean), J. Acoust. Soc. Kr. 25, 339-345 (2006).
Supported by : 국방과학연구소