General Electric Co., Advanced Technol. Labs., ATL Bldg., Moorestown Corporate Ctr., Moorestown, NJ 08057
General Electric Co., Moorestown, NJ 08057
Comparisons of commonly used numerical models of acoustic propagation are performed over a wide frequency band in selected shallow-water environments. The models include range-independent propagation loss codes, such as Colossus II and Generic Sonar model (GSM), as well as range-dependent codes, such as SNAP and a wide-angle split-step parabolic equation (PE) model. For both range-independent and range-dependent shallow-water environments, SNAP model predictions typically provide close approximations to measured propagation loss data. Alternatively, large differences and model biases are generally prevalent in comparisons between measured data and Colossus II or PE predictions. Comparisons between the PE and GSM models are presented for sound propagation in surface duct environments. Results pertinent to the sensitivity of shallow-water propagation loss predictions to the amount of range dependence in environmental quantities, such as sound speed, bathymetry, and bottom-interaction parameters, are provided. Advanced 3-D visualizations are shown that illustrate the sensitivity of the optimum frequency of acoustic propagation in shallow water regions to variations in source--receiver geometries and environmental quantities.