EFD and CFD for KCS heaving and pitching in regular head waves

摘要

The KCS container ship is investigated in calm water and regular head seas by means of EFD and CFD. The experimental study was conducted in FORCE Technology's towing tank in Denmark and the CFD study was conducted using the RANS code CFDSHIP- IOWA. Three speeds have been covered and the wave conditions were chosen in order to study the ship's response in waves under resonance and maximum exciting conditions. In the experiment the heave and pitch motions and the resistance were measured together with wave elevation of the incoming wave. The model test was designed and conducted in order to enable UA assessment for the measured data. The results show that the ship responds strongly, when the resonance and maximum exciting conditions are met. With respect to experimental uncertainty, the level in calm water is comparable to PMM uncertainties, while the level is higher in waves. Concerning the CFD results, the computation shows a very complex and time varying flow pattern. With respect to the integral quantities, a comparison between EFD and CFD shows that the computed motions and resistance in calm water is in fair agreement with the measurement. In waves the motions are still in fair agreement with measured data, but larger differences are observed for the resistance, particularly for the amplitude of the resistance time history.