The scattering of sound from fluid-loaded plates

Abstract

The scattering of sound waves from a finite strip plate under conditions of heavy fluid loading is numerically simulated. Both baffled and unbaffled geometries are considered, and results for the nearfields and farfields are obtained. Under conditions of heavy fluid loading, scattering effects due to the plate elasticity are generally small unless the excitation frequency is close to a resonance frequency of the fluid–plate system. The general behavior of the fluid–plate system and the frequencies, radiation efficiencies, widths, and strengths of the resonances are determined. With these results, one can determine the relevance of such phenomena in a variety of applications. The reliability of predictions for the resonance parameters based on simple modeling techniques is evaluated. The results indicate that the frequencies and effective masses of the resonances can be reasonably approximated. However, the radiation efficiencies are difficult to estimate because of the effects of the strong fluid loading. In the unbaffled case, modeling techniques based on vacuum mode shapes tend to substantially underestimate the radiation efficiency; in the baffled case, such techniques tend to substantially overestimate the radiation efficiency.