Abstract
Ship accidents that entail flooding may lead to disastrous consequences which could be avoided or mitigated based on the knowledge of damaged ship dynamics. The dynamic behaviour of a damaged hull is a complex phenomenon involving the interaction of the flooded water and the ship motions. The presence of a damage opening allows water flow into and out from the compartment, which further complicates the mathematical description of the problem. A fast simulation method, based on the lumped mass approach, is developed and presented. The lumped mass path in space depends on free-surface inclinations that differ from the ship angles of the roll and pitch. The viscous effects in the floodwater dynamics are implemented based on the model for the dissipation of the energy of standing waves in rectangular rooms. The method applies to both the transient stage of flooding and to the dynamic behaviour of a flooded ship in regular waves. In the first case, viscous effects are implemented considering the water in the compartment variable with time. Several case studies are carried out on three different hull models: Transient stage of flooding, roll decay of the damaged hull, and steady state responses in waves are simulated and compared with available experimental data.
Highlights
The improvement in the safety of a damaged ship is oriented towards simulation-based guidelines on critical scenarios [1,2]
The dynamic behaviour of a damaged hull is a complex phenomenon involving the interaction of the flooded water and the ship motions
The current paper presents improvements of the method developed in [20,21], accounting for the water exchange through the damage opening in ship dynamics and accounting for longitudinal acceleration effects in the free-surface inclination
Summary
The improvement in the safety of a damaged ship is oriented towards simulation-based guidelines on critical scenarios [1,2]. CFD is used intensively for studying sloshing phenomena [8,9,10] and many efforts are made to couple them with the dynamics of a damaged ship in waves [7,11,12] Notwithstanding that these methods prove to yield accurate results, their computation time is still a limit for wider applications. In [20,21], a novel method in simulating water flooding and its effects on ship motions was presented It is based on the lumped mass approach, considering the inclination of a flat free-surface due to the action of the ship’s lateral acceleration and the more accurate position of the lumped mass. The comparison with the available experimental data [23,24,25] highlights the pros and cons of the fast model, according to the simulated damage cases and comments on the obtained accuracy
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