Numerical simulations for the safe return to port of a damaged passenger ship in head or following seas

This study investigated the motion responses and flooding behavior of a damaged passenger ship model, using numerical simulations of fluid dynamics and six degrees of freedom motion. The test condition was based on the safe return to port regulations, and the numerical investigation was performed by solving unsteady Reynolds averaged Navier Stokes equations, using CFDShip-Iowa program and SUGGAR++ library. The selected hull form was scaled model of a passenger ship provided by the Ship Stability Research Center at the University of Strathclyde, UK. A damaged compartment was located amidships. Computed ship motions in head and following seas in regular wave train were analyzed by fast Fourier transform and the computation results of the pitch, heave, and roll motions and the advance speed were compared with experimental data in the same test condition. The pitch and heave motions by the numerical analysis agreed well with the experimental results, but the computation overpredicted roll motions at the natural roll frequency. In head seas conditions, the advance speed was overpredicted, regardless of the wave amplitude and period. In addition, flow behavior around the course-keeping model was investigated, in terms of the free-surface wave, hull wake, and flooding behavior.