Computer Programs to Calculate Normal Mode Propagation and Applications to Analysis of Explosive Sound Data in the BIFI Range
NAVAL UNDERWATER SYSTEMS CENTER NEWPORT RI
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This report describes two computer programs that use normal mode theory to predict acoustic propagation and discusses the use of these programs in analyzing explosive data taken in a series of shallow water tests. Program S1441 calculates normal mode propagation in a medium in which the stratification is constant with range program S1548 computes normal mode propagation when the horizontal stratification is assumed to vary slowly with range. The range of the tests indicate that the introduction of horizontal stratification in program S1458 provides an improved comparison with measured data. Physical explanations are provided for the previously observed minimum in propagation loss at about 125 Hz and for the nonlinear relationship, at certain frequencies, between propagation loss and size of the negative sound gradient observed. In addition, bottom loss was determined in the BIFI Block Island Fishers Island range for a wide range of frequencies and thermal conditions.
- Computer Programming and Software