DYNAMIC CHARACTERISTICS OF CYLINDRICAL TANKS WITH PERIODIC INITIAL IRREGULARITIES ON SIDE WALLS
Theoretical analysis of dynamic behavior of upright cylindrical tanks with initialirregularities on shell is conducted to investigate the effect of irregularities on natural frequenciesof liquid storage tanks. The distribution of hydrodynamic pressure in the tank with irregularitieson wall is derived by velocity potential function. The irregularities are considered as the initialdisplacements of the tank. Based on Hamilton's principle, free vibration equations of tank withinitial irregularities on side wall are obtained by means of a discretization scheme in which theshell is modeled by semi-analytical finite elements. Not only the effect of the irregularities onhydrodynamic pressure, but also the coupling effects among circumferential modes areconsidered. The numerical results show that the influence of the irregularities on certain naturalfrequencies of the tank is considerable.