Experimental investigation on stability of intact and damaged combatant ship in beam sea

The stability of damaged ship is influenced by several factors including encountered waves, ship motions, floodwater behaviour and interactions between ship motions and floodwater. The behaviour of floodwater is highly nonlinear so that physical experiment method is one of the best ways to obtain the assessment of damaged ship behaviour. The present study mainly addresses the experimental study of stability of an intact and damaged combatant vessel in beam waves. Tests are carried out at Kelvin Hydrodynamics Laboratory, University of Strathclyde, Glasgow, UK with a double-bottom naval combatant vessel DTMB 5415, which commonly appears in Benchmark studies for experimental investigation and the validation of numerical simulations. A 1/51-scale ship model was used in model tests. Free rolling decay tests with and without restricted constraint are implemented in calm water, while the model is restrained at the bow and stern during the wave excited oscillation tests. In order to investigate the performance of the intact and damaged ship in the beam the damaged opening locates at starboard near the midship so that floodwater would ingress and egress from the opening where two compartments would be flooded. According to the results, it can be shown that with the damaged opening, floodwater dynamics, including the interaction with water and sloshing effect in the compartments have a significant impact on the performance of the ship and loads acting on the ship’s roll motion. Nonlinear behaviour of the RAOs of all tests are given to provide the benchmark results for prediction with CFD methods further