In a submerged rigid oil storage tank it is possible to evaluate the internal and external hydrodynamic forces separately. Internally the forces are due to internal waves generated at the oil-water interface. Externally, they are due to radiated waves. When such a tank is made of steel, at it is usually the case, the internal and external forces get coupled through the flexibility of the shell, hence their solutions become inseparable. The following is an analytical treatment for the case of a flexible tank it expands the solution of the rigid tank to include the shell flexibility effect. The submerged tank is assumed to be subject to a harmonic lateral ground excitation.

In a submerged rigid oil storage tank it is possible to evaluate the internal and external hydrodynamic forces separately. Internally the forces are due to internal waves generated at the oil-water interface. Externally, they are due to radiated waves. When such a tank is made of steel, at it is usually the case, the internal and external forces get coupled through the flexibility of the shell, hence their solutions become inseparable. The following is an analytical treatment for the case of a flexible tank it expands the solution of the rigid tank to include the shell flexibility effect. The submerged tank is assumed to be subject to a harmonic lateral ground excitation.