Modeling the acoustic color of large aggregations of fish

Abstract

The Naval Surface Warfare Center Panama City Division has developed a 3-D finite-element computer simulation system, PC-ACOLOR, for modeling the “acoustic color” (target strength as a function of frequency and aspect angle) of realistic elastic objects, either singly or in aggregations, that are near the bottom of the ocean or in deep water. It employs 3-D continuum mechanics throughout the entire computational domain. All objects and fluids are treated collectively as a single heterogeneous continuum; no engineering approximations are used anywhere. PC-ACOLOR was developed originally for modeling manmade structures, but it is intrinsic to finite-element modeling that the same code can be applied, unaltered, to any elastic objects, whether they be manmade structures or biological organisms. The talk will give an overview of PC-ACOLOR: structural acoustic concepts; modeling techniques; verification and validation; and examples of different types of objects that have been modeled, including aggregations of many fish.