Numerical modeling of a multi degree freedom system consisting of heave, pitch and surge motions for the conversion of sea wave energy

Abstract

In this study, we present a point absorber wave energy converter model of a multi degree freedom system. This converter uses heave, pitch, and surge motions in order to absorb energy. Given that the function of the point absorber converters is dependent on the frequency of the wave excitation, the maximum power is obtained when the frequency of the system and the wave frequency are equal so the greatest oscillation occurs in the system. Therefore, using several natural frequencies for the system can help achieve the resonance condition. For this purpose, in addition to heave motion mode, other motion modes can also be used in order to gain more power in the system. The process of modeling and analyzing of the system in the first step was only by using heave's motion mode. But in the next step, the effect of pitch and surge's motions were added. Finally, the power absorbed by the system in these two steps was compared with each other. Increasing the power absorbed by the system is one of the results of this study.