ASA 126th Meeting Denver 1993 October 4-8

5aUW11. Analysis of the acoustic field via spectral decomposition.

Guy V. Norton

NRL-SSC, Stennis Space Center, MS 39529-5004

Spectral decomposition has been used by various authors as a calculation technique for acoustic propagation in range independent and recently range dependent ocean environments. One of the methods' strong points is that it maps the initial acoustic field at each given depth point in the waveguide into horizontal wavenumber space. Since the field is now expressed in wavenumber space, analogous to normal mode theory, various acoustic quantities can easily be calculated. These quantities such as the group velocity or the incident field expressed in terms of the plane wave spectrum in the past were calculated using normal modes. However, since all that is required to initiate the method is a complex acoustic field evenly space in depth of the waveguide, the method has been coupled to the output of a PE model, in order to analyze that field. The associated theory and numerical examples will be given. [Work sponsored by ONR.]