Acoustic-Structural Coupling — Vibro-Acoustics & NVH

What is the fundamental difference between structural and acoustic analysis of a vibrating panel?

Structural analysis asks: how does the panel deform, what are the stresses and natural frequencies? Acoustic analysis asks: what sound pressure field does the vibrating panel create in the surrounding fluid, and how much sound power is radiated? Coupling is through normal velocity at the panel surface — the structural velocity must match the fluid particle velocity.

When does acoustic radiation damping significantly affect structural response?

Acoustic radiation damping is important when the structure radiates efficiently into a dense medium. In air, radiation damping is negligible compared to structural damping. In water, the acoustic radiation load can be comparable to structural inertia. Underwater acoustic problems almost always require two-way fluid-structure coupling for accurate structural response.