Qualitative and Quantitative Validation of a Numerical Code for the Realistic Simulation of Various Ship Motion Scenarios

There is an ongoing discussion on safety guidelines to be considering more recent developments in ship design. Numerical simulations of ship motions are considered as powerful tool for the safety evaluation of a given design. However, the consequent use of numerical codes calls for their thorough validation which has to be performed both qualitatively and quantitatively. This paper focuses on a code used and further developed by the Flensburg Shipyard. For its validation, the capsizing scenario in steep wave sequences is realized in the wave tank first. The dedicated computer controlled experimental technique ensures the exact phase correlation of wave excitation and resultant ship motions. Thus, the registered wave and the track of the ship model in the model test serve as input to the numerical simulation which results in the specific motion time traces. These are now directly compared to the motion registrations from the model tests. First results of the validation by direct comparison of time series have been presented in earlier publications, still with the restriction that only a few cases have been investigated. In this paper, the promising method is applied to another scenario in a long-crested sea state including steep wave combinations. Different aspects are discussed which results in the conclusion that the method is feasible for free running ships in stern and stern quartering seas.