Comparison of Straight Line Geometry Versus Curvilinear Ray Tracing Technique.

摘要

CONGRATS is a collection of ray tracing programs designed to model acoustic propagation and reverberation. Although these programs produce a variety of useful printed and plotted output, there occasionally appears a need for specific information that is not provided by the basic programs. Rather than develop a large number of individual programs, it is usually simpler to modify the existing program in response to a particular need. This ease of modification makes the CONGRATS series an extremely versatile tool. In the present case a modified version of NUSL Program S0991, the CONGRATS Ray Plot Program, was used to construct tables showing propagation loss vs initial inclination angle for both continuous velocity gradient and constant velocity profiles. The tables also include horizontal range, slant range, and incident angle at the target as a function of initial angle. Propagation loss consists of spreading loss and attenuation loss. This memorandum includes a discussion of the tables, a comparison of the two methods of computing range and propagation loss, examples of the output, and graphs illustrating the discrepancy between the two techniques.