Numerical study of the stern flap effect on catamaran' seakeeping characteristic in regular head waves

A numerical study was conducted to investigate the stern flap effects on catamaran's hydrodynamic performance in regular waves. An unsteady RANS code HUST-ship was used to predict the catamaran hydrodynamic performance in different sea states. Experimental tests were performed to assess the accuracy of the CFD code. Validation of the numerical method was conducted for time-steps/grid independent studies and uncertainty analysis of the numerical simulation results includes evaluation of resistance and ship motions. The comparisons of CFD and EFD results agree well with each other. Then numerical studies on the stern flaps effect for the catamaran's hydrodynamic performance in regular head waves were presented. Different lengths of stern flaps have been considered. The effects of stern flap on resistance, heave and pitch motions were evaluated for different wave lengths and amplitudes. The catamaran's resistance, heave and pitch motions reached peak values near the resonance frequency of the catamaran models. The results demonstrate that both the resistance and ship motions could be reduced when install the stern flap for the catamaran.