Objective The motion attitude of oscillating buoy wave energy converters significantly impacts energy capture, and the compartmentalization characteristics of the buoy are closely related to its motion attitude. Therefore, it has significant importances to investigate the influence of compartmentalization on the buoy's energy harvesting capability.

Method This paper established a model for the coupling effects between point absorber wave energy converters-mooring systems. The mooring system was selected to be a segmented form of anchor chain-steel wire rope-anchor chain, and the linear elastic steel wire rope was equivalent to a linear PTO (Power Take-off) system to simulate the energy harvesting process of the buoy. By designing different compartmentalization patterns and adjusting the water mass within the compartments to achieve varied internal mass distributions, frequency-domain analysis and coupled mooring time-domain analysis were conducted on the compartmentalized buoy. This approach explored the mechanisms by which different internal mass distributions affect the buoy's hydrodynamic characteristics and energy harvesting capacity.

Result The study reveals that altering the internal mass distribution within a buoy can significantly enhance its energy capture capability. When the internal mass of the buoy is unevenly distributed, the maximum CWR (Capture Width Ratio) for the buoy in form (d) which is characterized by a tilt towards the incident wave direction and symmetrical mass distribution along the wave direction, can reach 97%. Conversely, when the internal mass of the float is evenly distributed, with the internal mass dispersed in the compartments at the edge of the float, the heave response of the float increases significantly by 23%. Furthermore, when the internal mass distribution within the buoy is uneven, and the buoy is symmetrically distributed along the orthogonal direction of the incident wave while also tilted towards this direction, as exemplified in form (e), the heave motion displacement reaches 1.573 m, which is significantly greater than that of other buoy forms. This corresponds to a stronger ability to capture wave energy.

Conclusion Based on the established compartmentalized buoy model and its hydrodynamic analysis in wave motion, this study can provide a reference for optimizing the internal mass distribution design of point-absorbing wave energy conversion devices for power generation.