Modeling three-dimensional underwater acoustic propagation over multi-layered fluid seabeds using the equivalent...

Area of Science:

• Ocean Acoustics
• Computational Physics
• Wave Propagation

Background:

• Accurate modeling of underwater acoustic propagation is crucial for sonar systems and marine research.
• Existing methods often face computational challenges with complex environments and large scales.
• The equivalent source method (ESM) offers a framework but requires efficient numerical solutions.

Purpose of the Study:

• To develop an efficient and accurate three-dimensional (3D) underwater acoustic propagation model.
• To incorporate multi-layered fluid seabeds and complex sound speed profiles.
• To accelerate the equivalent source method (ESM) for large-scale simulations.

Main Methods:

• Developed a 3D underwater acoustic propagation model based on the equivalent source method (ESM).
• Solved the Helmholtz equation by superposing fields from equivalent sources, imposing boundary conditions to derive a linear system.
• Employed iterative generalized minimum residual (GMRES) method with pre-corrected fast Fourier transformation (PFFT) for efficient matrix-vector products.
• Integrated an FFT subgrid scheme to handle layered water columns with varying sound speed profiles.

Main Results:

• The PFFT-accelerated ESM (PFFT-ESM) significantly reduces numerical costs for 3D large-scale propagation.
• Simulations over a Gaussian canyon validated the accuracy of the PFFT-ESM.
• Demonstrated the model's capability for 3D scattering problems, including simulations with corrugated surface waves.

Conclusions:

• The PFFT-ESM provides an efficient and accurate solution for 3D underwater acoustic propagation problems.
• The model effectively handles complex scenarios, including multi-layered seabeds and sound speed variations.
• This method enables efficient large-scale acoustic simulations and scattering analysis in underwater environments.