RAYLEIGH-RITZ METHOD IN COUPLED FLUID-STRUCTURE INTERACTING SYSTEMS AND ITS APPLICATIONS

Based upon general thin shell theory and basic equations in fluid mechanics, the Rayleigh-Ritz method for coupled fluid-structure free vibrations is developed for arbitrary tanks fully or partially filled with inviscid, irrotational and compressible or incompressible fluid, by means of the generalized orthogonality relations of wet modes and the associated Rayleigh quotients. It is pointed out that the natural frequencies of the coupled vibrations may be approximated by a linear combination of a series of trial functions which satisfy the boundary conditions of the problems, Equations for calculating the eigenvalues and eigenvectors are presented. An example concerning application of the Rayleigh-Ritz method to predicting the basic frequency of a fluid-filled circular cylindrical tank is provided. Calculated numerical results show good agreement with others of available. (C) 1995 Academic Press Limited