Research On Automatic Control Flap System And Wave Moment Of WPC

With the development of high performance ships, Wave Piercing Catamaran is moreand more popular to people due to its good seakeeping and high speed. So there aregreat development prospects for WPC in both military and civilian area. But WPC alsohave some shortcomings as a transport platform. Such as the excessive longitudinalmotion occurs when the speed is high, which results in seasickness rate increase andaffects ship’s comfort. In order to further improve the damping effect and maximizingthe ‘wear’ characteristic of WPC. To equip longitudinal stabilizer and adopt the optimalcontrol strategy is especially necessary.In this paper, a MATLAB program is written based on the strip theory for thecalculation of the WPC’s longitudinal response in frequency range. The accuracy of theprogram can be verified by comparing its calculation results with the model test results inregular wave. The automatic control flap system is introduced based on the traditionalhydrofoil and stern flap combination for longitudinal stabilization. Optimal phase angleof the flap motion can be found according to the calculation and experiment analysis.Meanwhile, the hydrodynamic coefficient of moving flap can be derived and added to theprogram based on the existing hydrodynamic calculation method of fin. Then calculationand irregular wave tests of WPC with optimum controlled were finished. The comparingresults of light body model, fixed flap model and automatic control flap model show that,automatic control flap system can greatly reduce the pitching amplitude and verticalacceleration of WPC.Calculation of WPC’s longitudinal moment on the wave is very important for itsstrength checking. According to the hydrodynamic forces and wave exciting forcecalculation method for longitudinal motion prediction in strip theory, composition ofwave induced loads was analysed. Then ship moment response in frequency range can be calculated and validated through comparing with the specification requirements. Finally,short-term and long-term prediction of ship moment can be done based on wavecharacteristics.