Galerkin equivalent sources method for sound field reconstruction around diffracting bodies

Area of Science:

• Acoustics
• Numerical Modeling
• Signal Processing

Background:

• Accurate numerical models are crucial for 3D acoustic imaging, especially for characterizing radiating objects.
• Free field transfer functions often oversimplify acoustic propagation by assuming object transparency, leading to inaccurate characterization.
• Equivalent Source Methods (ESM) offer a powerful approach to simulate complex scattered sound fields.

Purpose of the Study:

• To propose and evaluate a novel acoustic imaging algorithm, Galerkin ESM.
• To enhance the simulation of scattered sound fields by incorporating Neumann boundary conditions.
• To compare the performance of Galerkin ESM against existing imaging algorithms using both numerical and experimental data.

Main Methods:

• Developed Galerkin ESM, an acoustic imaging algorithm using equivalent sources.
• Sources are optimized to match microphone pressures and satisfy Neumann boundary conditions.
• Employed projected matrix inversion and backpropagation for direct synthesis of the acoustic pressure field.
• Compared Galerkin ESM with free field and computed transfer function methods.

Main Results:

• Galerkin ESM demonstrated superior performance in acoustic imaging compared to conventional methods.
• The choice of transfer model significantly impacts the accuracy of acoustic characterization.
• Numerical and experimental validation confirmed the effectiveness of the proposed Galerkin ESM.

Conclusions:

• Galerkin ESM provides a more accurate and robust method for 3D acoustic imaging.
• The algorithm effectively synthesizes the acoustic pressure field around diffracting bodies.
• This advancement improves the characterization of radiating objects in acoustic imaging applications.