An analytical and computational study of the low frequency dynamic responses of a submerged hull

This paper studies the low frequency vibrational behaviour of a submerged hull. The submerged hull is modelled as a finite fluid-loaded cylindrical shell closed at each end by circular plates. The external pressure acting on the hull due to the fluid loading is analytically calculated using an infinite model. Three load excitation cases of the hull are considered. The effect of the individual circumferential modes, in particular, the breathing and bending modes, on the hull structural responses is studied. A more complex hull model including stiffeners and bulkheads is then examined. Results from the analytical models are compared to computational results obtained from a fully coupled finite element/boundary element model. The elastic structure is modelled using quadratic finite shell elements while the model for the infinitely extended fluid domain is represented by linear boundary elements. The two-way fluid structure interaction between the structure and fluid is taken into account using a Mortar coupling scheme.