Vibro-acoustics of infinite and finite elastic fluid-filled cylindrical shells

The classical model of an elastic fluid-filled cylindrical shell is used for analysis of its vibrations. The model is based on thin shell theory, standard linear acoustics and the heavy fluid-loading coupling concept. First, several important features of performance of a fluid-filled shell not yet fully explored in literature e.g. the difference between kinematic/forcing excitations, acoustic source type identification (monopole/dipole) and energy transfer between fluid and shell are studied. Then the discussion is extended to finite fluid-filled shells by application of the Boundary Integral Equations Method (BIEM). Two techniques for solving the equations deduced from the BIEM are discussed and investigated with respect to convergence, respectively, Boundary Elements (BE) and modal expansion. Successively, the implementation of the BIEM is validated against numerical and experimental results for the simplified case of an empty shell. Finally, impedance boundary conditions for a fluid-filled shell in an assembled piping system and computations of its resonances and forced response using the BIEM are discussed.