Dynamic analysis of a partially-filled cylindrical-conical-cylindrical shell representing a pressure vessel

A base-supported partially-filled fluid-shell system representing the pressure vessel of a fast reactor is studied. The shell is made of two cylindrical parts joined through a conical part. The shell is characterized using Donnell's theory, while the fluid is modeled using a velocity potential approach. Compatibility and interface conditions led to the energy functional, minimization of which yielded natural frequencies. The approach was validated against previously studied joined systems. Parametric studies revealed that vibration frequencies of the fluid-shell system (i.e., bulging frequencies) are comparable to shell-only vibration frequencies if only the lowermost part is filled. Vibration frequencies of the free fluid surface (i.e., sloshing frequencies) do not change materially with fluid height if most of the vessel is filled. Present study did not consider the coupling between bulging and sloshing modes, which may need to be considered for a completely-filled vessel with a large base radius (e.g., > 3 m) as the two sets of frequencies for such systems can be comparable.