A unified fast multipole boundary element method for acoustic scattering from objects near a fluid-fluid interface

Area of Science:

• Acoustics
• Computational Mechanics
• Numerical Analysis

Background:

• Modeling acoustic scattering from elastic inclusions near fluid interfaces is computationally challenging.
• Existing methods often struggle with the complexity of semi-infinite domains and elastic properties.

Purpose of the Study:

• To develop an efficient and accurate computational method for acoustic scattering from elastic inclusions at fluid-fluid interfaces.
• To adapt the unified fast multipole boundary element method (FMBEM) for this specific problem configuration.

Main Methods:

• Utilizing the parallel broadband Helmholtz FMBEM for fluid domains and FEM/elastodynamic FMBEM for the elastic inclusion.
• Formulating boundary integral equations to account for interface transmission and reflection.
• Employing a truncated boundary mesh for the fluid-fluid interface.

Main Results:

• The FMBEM model accurately simulates acoustic scattering with elastic inclusions between fluid half-spaces.
• Errors due to mesh truncation can be minimized by appropriately sizing the mesh.
• The method demonstrates a computational cost of O(N log N).

Conclusions:

• The unified FMBEM offers a computationally efficient solution for 3D acoustic scattering problems with elastic inclusions at fluid interfaces.
• Boundary-only discretization and simplified mesh truncation contribute to the model's efficiency.
• This approach provides a robust tool for analyzing complex acoustic phenomena in geophysics and engineering.