The presence of a sub-structure in a cylindrical shell gives rise to dynamic interactions, including resonance effects, which have an influence on the radiated acoustic field. The lowest mode of the sub-structure may interact vigorously with a higher order mode of the shell. In this paper a frequency window method is used to analyze the forced motion of the immersed shell/sub-structure system in a frequency range of interest, namely one corresponding to a higher order mode of the shell. A particular example is concerned with a springmass system, which is attached to the shell. Three cases of forced harmonic motion are considered. The radiated energy is computed as a function of the frequency. It is shown that excitation at a relatively high frequency, corresponding to a higher order mode, stimulates energy radiation into the acoustic medium via lower order modes. The radiated energy for the shell/sub-structure system is compared with that for a shell without an oscillator subjected to the same input force.
ASJC Scopus subject areas
- Mechanical Engineering