Comparative Modeling and Analysis of Wideband Low Frequency Acoustic Propagation in the Shallow Water Environment
Abstract
This grant was supported by the Ocean Acoustics Program in the Sensors and Systems Division of the Ocean, Atmosphere and Space Department of ONR. This project was a direct follow-on, scientifically speaking, of research performed under Grant N00014-95-1-0029, 'Analytical and numerical study of shallow-water acoustic mode coupling from solitary internal waves'. Modeling was done at frequencies of 50 to 2400 Hz in order to determine acoustic mode coupling behavior in shallow waveguides with a variety of basement properties. Modeling was done with a flat bottom, but this led to interesting but unphysical propagation properties at frequencies above 800 Hz. One mode with unphysically low bottom interaction existed at each modeled frequency. These modes will not persist in reality, so the runs needed to be repeated with a sloping bottom, stalling our progress. The FEPE parabolic equation code of NRL was initially used for modeling. To solve the problem we switched to the NRL RAM code and then modified it to enable simpler substitution of variable ocean waves, water depths, and bottom types. The delay caused by this anomalous model behavior, while illuminating, had delayed interpretation and publication of our results. Further analysis of these effects is now underway under Grant N00014-01-1-0772, 'Capturing uncertainty in the common tactical environmental picture'.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 15, 2002
- Accession Number
- ADA404185
Entities
People
- George V. Frisk
- James C. Preisig
- Timothy F Duda
Organizations
- Woods Hole Oceanographic Institution