The Influence Of Ocean Internal Waves On Sound Propagation

It is a basic task of ocean acoustics to research the influence of ocean environment on sound propagation. Ocean internal wave can change the ocean sound velocity profile, and cause the sound signal fluctuation, so it is necessary to research the influence of ocean internal waves on sound propagation.In recent years, some ocean internal wave models and sound propagation models have been established, such as GM72, GM75, Kraken, and FOR3D. In this thesis, parabolic equation approximation, FOR3D, is used to research the influence of ocean internal waves on sound propagation.In this thesis, ocean linear internal waves and internal solitary waves are introduced, and their perturbations of ocean sound velocity profile are analyzed and simulated. According to the internal wave parameters acquired in an ocean experiment, the sound propagation from 20Hz to 1500Hz in different environments is simulated. It can be seen that the internal waves can change the sound transmission loss, especially when the source has a low depth and the frequency of source is between 300Hz to 1500Hz. The result also shows that PE approximation has high accuracy and fast computation speed. It is a useful tool for the research on sound propagation when internal waves exist.