Modal decomposition of exterior acoustic-structure interaction

Area of Science:

• Acoustics
• Structural Mechanics
• Fluid Dynamics

Background:

• Analyzing sound radiation from submerged structures is crucial for understanding acoustic phenomena in marine environments.
• Existing methods often struggle to accurately capture the complex interactions between structures and surrounding fluids.

Purpose of the Study:

• To develop and present a modal decomposition technique for analyzing sound power radiated by externally excited structures in heavy fluids.
• To investigate the contributions of individual fluid-loaded structural modes to the total radiated sound power.

Main Methods:

• Fluid-loaded structural modes were calculated using polynomial approximation and symmetric linearization of a nonlinear eigenvalue problem.
• Eigenvalues and eigenfunctions for a fluid-loaded sphere (with and without internal structures) were determined.
• Modal sound power contributions were calculated using both fluid-loaded structural modes and acoustic radiation modes.

Main Results:

• The study presents eigenvalues and eigenfunctions for a fluid-loaded sphere, demonstrating the technique's application.
• Individual modal contributions to resistive and reactive sound power were calculated.
• Superposition of modal contributions was compared against the harmonic solution of the forced problem, validating the approach.

Conclusions:

• The modal decomposition technique effectively analyzes sound power contributions from submerged structures.
• The method provides insights into the acoustic behavior of fluid-loaded structures, aiding in design and analysis.
• Accurate calculation of fluid-loaded modes is essential for predicting radiated sound power.