The natural vibration characteristics of a water-shell tank interaction system

The simulation of liquid-tank interactions is important for LNG-tank designs and safe operations. This paper presents some research results developed by authors. Integrated systems studied are formulated using a generalised fluid-structure interaction theory. Various suitable boundary conditions applied to the system are considered, which describes free surface disturbances, dynamical couplings on wet interfaces as well as prescribed pressures caused by explosion waves. The mixed FE substructure-subdomain method and the corresponding computer code adopting the solid displacement and the fluid pressure as variables are described. A water-shell tank interaction system and a 2-dimensional section of a LNG-tank system are numerically simulated using the developed code. The natural frequencies and modes of these two systems are presented. To reveal the filled air influence on the natural vibration characteristics, a case of air-water-shell interaction is investigated. The numerical results are compared with the available numerical and experimental results to demonstrate and validate the method and the computer code. Some guidelines are provided for dynamic designs of liquid-container systems involving fluid-solid interactions.