Research On The Implementation And Application Of Parabolic Equation Method Based On Higher-order Pade Approximation

Mastering the rules of underwater sound propagation is a very effective tool to realize the ocean. Most ocean areas round our country are shallow water environment. The sound propagation in the shallow water becomes complex since the influence of elastic ocean bottom and the sloping or variable bathymetry. The purpose of this thesis is to find a model to simulate sound propagation in realistic ocean environments so that we can master the sound propagation rules and predict the complex underwater sound field.In this thesis the parabolic equation methods based on the higher-order Pade approximation are successfully applied to establish seismo-acoustic propagation model. This model can compute the wave field in the ocean environment involving complex range and depth dependence and variable topography. The energy-conserving and rotated parabolic equation methods are analyzed to treat sloping fluid-elastic interfaces. The sound field computing programs of parabolic equation method based on Pade approximation are realized in language Matlab. Compared with the simulated solutions of other models, the precision of this program is verified.By the comparison between the sound field computations for some ocean environments, it is verified that this model is valid for sound propagation in elastic media. For the ocean waveguides that contain a weakly sloping bottom, both energy-conserving and rotated parabolic equation methods can provide accurate solution, and they are stable and efficient.