The effect of hydrostatic pressure fields on the structural and acoustic response of cylindrical shells

Abstract

The effects of external hydrostatic pressure fields and fluid loading on the structural and acoustic response of a point-driven infinitely long circular cylindrical shell were examined over a range of frequencies. The external pressure field was modeled using static prestress terms in the shell equations of motion, and the structural response was characterized by the driving point admittance and the circumferential resonant frequencies. The acoustic response was quantified through calculation of the radiated sound power, both in an overall sense and on an individual modal basis. The analysis was performed for the in-air case as well as for the in-water case. The structural response was found to be strongly affected by fluid and pressure, resulting in significant resonant frequency shifts. However, the overall acoustic response was shown to be nearly independent of the external pressure field, both in air and in water. In addition, it was shown that relatively fewer modes contribute significantly to the sound radiation for the submerged shell as compared to the shell in air. In both cases, the sound generation was controlled by the low-order nonresonant modes.