Roll motion response analysis of damaged ships in beam waves

The seakeeping performance of a damaged ship is highly correlated to the wave incident direction. Therefore, predicting the motion responses of a damaged ship under various incoming waves is important. In this study, the seakeeping performance of a DTMB 5415 model is investigated by focusing on its roll motion under beam wave condition. The model performance under an incident wave angle (α) of 180° is widely studied experimentally and numerically. But the behaviours of a damaged ship under α = 0° remain unknown. This study aims to analyse the damaged ship motion performance under this rarely studied condition. The volume of fluid (VOF) free-surface technique is used to solve the Reynolds-averaged Navier–Stokes equations, as well as with the dynamic overset technology that handles the mesh update, the wave generation, time step and fast Fourier transform are utilised to validate the effectiveness of the adopted method. The numerical results are validated against the experimental results obtained when α = 180°. The same methodology is extended to investigate the three-degrees-of-freedom motion (roll, pitch and heave) at α = 0°. Results show that the roll motions under the two wave conditions greatly differ from each other. The discussions highlight the analysis of the possible reasons for this difference. •Current research deals with beam wave that from the opposite direction of the damaged side.•How the ship motion with beam wave from the same direction of the damaged side remain unknown.•The motion response characteristics with two wave directions are compared.•The interaction between the ship and the floodwater is analysed.•The differences between the two wave directions and the possible reasons are examined.