Eigencharacteristics of fluid filled tanks: an extended symmetrical coupled approach

In the numerical analysis of the eigen behaviour of large liquid and gas storage tanks, an important role is played by initial pre-stressing of such thin-walled structures due to high fluid pressure and gravity. In a majority of numerical simulations, the finite state of deformation is first calculated, following which small, linear vibrations are superimposed on the finite state. This paper is devoted to refinement and assessment of the basic Eckart superimposed eigencharacteristics problem simultaneously stated in fluid and thin-walled structures. Eckart's coupled approach leads to variational structure-fluid coupling in the so-called acoustic approximation. In order to verify the feasibility and correctness of the symmetrical Eckart approach, finite element discretization and a calculation example of a rectangular tank are presented. The calculated results are compared with literature ones.