Research On Finite Element Method In Ocean Acoustic Propagation Problems

Numerical methods such as the finite element method can be used in ocean acoustic propagation problems with irregular seabed and rough sea surface or other complex marine environment,increasingly attention has been laid on underwater sound field calculation and characteristic analysis . This paper starts with the basic theory of finite element method for solving wave equation,then establish sound propagation models with point source at low-frequency in the acoustic module simulation platform of general-purpose software Comsol Multiphysics 5.0 to implement the finite element algorithm.The two-dimensional wedge-shaped waveguide with fluid bottom condition is used as benchmark model to test other propagation model is accurate or not.Firstly,the fluid bottom models have been established, the COMSOL finite element results showed a good accuracy by comparing with other algorithms.Then simulates sound propagation model with elastic seabed at low frequency and analyzes the influence of the shear wave effects and interface wave phenomena during propagation. The actual ocean environment is a spatial varied waveguide,the COMSOL propagation models is extended to three-dimensional and the propagation characteristics has been discussed.In addition,this paper makes a comparison of the computational efficiency and hardware consumption in two-dimensional and three-dimensional COMSOL models,confirmed the optimal scope of PML.Lastly,an APP based on the three-dimensional plane-parallel ideal waveguide has been presented with the APP builder,all of these provide a new ideal for better practical use in sound propagation problems with commercial finite element software just like COMSOL.