ABSTRACT
This chapter first distinguishes the mathematical models on the basis of their theoretical treatment of volumetric propagation. Then, as appropriate, further distinctions are made according to the specification of boundary conditions and the treatment of secondary volumetric effects such as attenuation due to absorption, turbidity, and bubbles. Basic acoustic models supported the more specialized category of sonar performance models. Propagation models are the most common type of underwater acoustic models in use. The theoretical basis underlying all mathematical models of acoustic propagation is the wave equation. The earliest attempts at modeling sound propagation in the sea were motivated by practical problems in predicting sonar performance in support of antisubmarine warfare operations during World War II. Formulations of acoustic propagation models generally begin with the three-dimensional, time-dependent wave equation. Depending on the governing assumptions and intended applications, the exact form of the wave equation can vary considerably.
