Abstract:

Several ocean acoustic computer models were used to analyze shallow-water, higher-frequency (around 4-kHz) acoustic data taken during a recent Navy exercise. This effort enlisted models (EFEPE-CM, FEPE, ASTRAL, RAYMODE) and computer resources (Cray C90, SGI Challenge-8, 386 desktop PC) that spanned the RDT&E modeling spectrum, from basic research to Fleet operations. The research models were used to identify and prioritize dominant physical mechanisms. Once these were known, errors and weaknesses in the operational models were easily identified and corrected. The result was consistent with predictions from the entire suite of models that compared favorably with data. Advantages were gained in computational speed and accuracy. An acceptable shallow-water, high-frequency, acoustic prediction was obtained in 2 s using a Fleet operational model (ASTRAL) and a 386 desktop PC computer. Two important lessons were relearned: (1) Current ocean acoustic research models include the necessary physics to make accurate high-frequency predictions in shallow-water environments, even when realistic sea-surface conditions dominate; and (2) the more physics included in the models, the less knowledgeable need be the model operators. Details and examples will be presented. [Work supported by ONR/NRL, MMoDS, AUAMP, and DoD HPC.]