Fluid-structure coupling by the entrained fluid in submerged concentric double-shell vibration.
Year: 1993
Type: article
Abstract: Vibrational characteristics of a point-driven "double shell" (two concentric submerged cylindrical shells coupled by the entrained fluid) are investigated.Strong-and weak coupling theories are proposed to model the interaction of how the inner and outer shells are coupled by the entrained fluid.Each theory is based on Flugge's infinite-shell equations, the Helmholtz wave equation, and boundary conditions at the fluid-struc ture interfaces which depend on the coupling situation.Strong coupling forms a stand ing wavefield in the entrained fluid; weak coupling, a free wavefield.Experiments are carried out where generalized near-field acoustical holography (GENAH) is employed to provide the experimental vibration characteristics in wavenumber-frequency space of the finite double-shell.It is confirmed theoretically and experimentally that the outer shell of the double shell exhibits two separate dispersion curves:A higher-frequency curve bears in-phase vibrations with respect to the inner shell and suggests a forced response of the inner shell; the other lower-frequency curve, out-of-phase vibrations, and an induced response of the outer shell.Fluid-structure coupling condition de finitely affects the lower-frequency curve, but barely the higher-frequency one.Com parison between theoretical and experimental results demonstrates the validity of the strong-coupling model.
DOI: 10.1250/ast.14.99
Author: Shigeru Yoshikawa
Institution: Defence Research and Development Organisation
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2081024301