A FAST NUMERICAL MODEL FOR EVALUATING THE STABILITY OF A DAMAGED SHIP IN REGULAR BEAM WAVES

Damage stability in waves, which reveals highly non-linear and complicated behaviors, is attracting more and more attention recently. In this paper, a fast numerical model for predicting the stability of a damaged ship in regular beam waves is presented and validated by the published model experimental data. The potential flow theory is applied to build the basic model. In the basic model, the flowrate through the breach is calculated through modified Bernoulli's equation. The compressibility of air and the phenomenon that air escapes from the air pocket in a bubble flow are simply simulated by modified Bernoulli's equation for compressible fluids and nuclei number density distribution function respectively. The lump mass method is introduced to estimate the sloshing force of floodwater inside the damaged compartment and roll damping is obtained from roll decay experiment of damaged ship. Then the numerical model is applied to the International Towing Tank Conference (ITTC) benchmark model in still water and the frigate hull named DTMB5415 in regular beam waves. Internal water height in the damaged compartment, roll decay of the damaged hull and motion responses in regular waves are calculated and compared with available model experimental data. It is confirmed that the results of the numerical model have a good agreement with the published experimental data.