Validation of Numerical Motion Simulations by Direct Comparison With Time Series From Ship Model Tests in Deterministic Wave Sequences

Ship safety under normal and severe weather conditions is determined by ship design, approval, and operation. Numerical simulation of ship motions has proven to be a valuable tool for ship design evaluation — not only for accident investigations and studies addressing fundamental stability related phenomena, but also during the design process. A sufficient number of simulations provide a data basis for polar plots to judge the ship’s situation in a sea state — defined by significant wave height and characteristic period — with respect to load case, encounter angle and ship speed. Application of data provided by numerical tools has to take into account the validity range of the model and has to be validated sufficiently by model test data. For providing useful validation data, the exact correlation of wave excitation and ship motion in model testing is indispensable. In the framework of the German research project SINSEE, this is achieved by a fully automated test procedure with a free running ship model in combination with deterministic generation of tailored realistic wave sequences and their transformation to the moving reference frame of the cruising ship. The resultant wave train can be directly correlated with time series of motions — registered by an optical system — and forces. In this paper, these methods are applied to investigate pre-simulated seakeeping scenarios in the model basin and compare the results directly to the simulation results.