A simulation model for ship response in flooding scenario

Recent ship damages underline the importance of an accurate intact and damage stability analysis. The stability of ships is presently determined by applying quasi-static methods, neglecting dynamic effects; for flooding scenarios, flow calculations are not carried out either. In general, for damage cases, water dynamics inside the compartment affect ship motions. It has been observed that some kind of vessels could experience large roll motions due to the sudden water ingress after damage. In this article, a non-linear tool for damage stability evaluation is presented, including water dynamics in a flooded compartment. In particular the transient stage of flooding is investigated. The flooded water has been treated using the lumped mass approach. A new method has been developed and applied in this article in order to model the water motions: the freesurface is assumed to be no more horizontal but dependent on ship and flooded water accelerations. The developed method is intended to be an intermediate approach between the quasi-static method (uncoupled) and fully coupled method. In coupling the flooded water motions with ship motions, no more unknowns are introduced: only ship lateral acceleration is used to determine the freesurface inclination of the flooded water. A valuation is carried out, comparing the numerical result from the simulations with the experimental studies on a barge model. Additional applications are carried out on the free roll motion of the TNK tanker model.