4aUW5. Understanding acoustic propagation in shallow water via animations.

Session: Thursday Morning, May 16

Time: 9:45

Author: John B. Schneider
Author: Patrick J. Flynn
Author: Shira L. Broschat
Location: School of Elec. Eng. and Comp. Sci., Washington State Univ., Pullman, WA 99164-2752


Modeling the propagation of acoustic energy in shallow water is difficult due to the complexity of the environment. Roughness at the air--sea interface and bottom, inhomogeneities in the water column and sediment, and discrete scatterers affect the propagation. Although many modeling techniques are available to study this problem, arguably none is general enough to provide robust and accurate results over a large region when several complicating physical features are present. Instead, simplifying assumptions are often made, and the effect of such assumptions on the model's validity is uncertain. Here, propagation in shallow water is studied via animations of the results obtained using the finite-difference time-domain method (a powerful, but computationally expensive, modeling technique with few inherent assumptions). Such animations provide insight into the relative importance of certain physical features that is not easily obtained from ``still'' data. Two different types of animations are discussed. One employs a ``side-by-side'' comparison in which time-domain propagation is shown in both the presence and absence of a certain physical feature. In the other, time is held constant and a physical feature is varied from frame to frame. Creation of animations using freely available software is also discussed. [Work supported by ONR.]

from ASA 131st Meeting, Indianapolis, May 1996