Aiming at the potential safety hazard of tension-compression buckling of riser caused by heave motion of floating offshore platform, the compensation mechanism of riser tensioner for system dynamic characteristics is studied. By establishing the dynamic model of the floating platform-riser tensioner-riser coupling system, the motion parameters of the platform are obtained by hydrodynamic analysis, and the dynamic response of the riser is solved by numerical integration method. Based on the multi-body dynamics model, the influence of the multi-degree-of-freedom coupling motion of the platform on the performance of the tensioner is quantified. The results show that the riser tensioner can effectively compensate 60%~70% of the platform heave motion under the multi-degree-of-freedom coupling motion of the platform, and significantly improve the stability and safety of the floating offshore platform-riser tensioner-riser system.

Addressing the challenges of low efficiency and instability in the passive energy extraction of wave-powered boat under wave conditions, a fluid-multibody coupled non-holonomic constraint model for an active control hydrofoil system is developed. The motion response and propulsion performance of the active propulsion mode are thoroughly investigated. The optimal propulsion interval of the hydrofoil under various wave conditions is analyzed through numerical simulation, and the optimization of the active control model on the energy harvesting of the hydrofoil propulsion mechanism is demonstrated by combining with the flume experiments. The results demonstrate that the active control model effectively enhances the flow structure generated by the hydrofoil, increasing surface pressure differences and stabilizing the wake vortex, which together improve the propulsive performance of the wave-powered boat. Additionally, a symmetrical pitch cycle of the hydrofoil proves to be more efficient in boosting power output, while torque input optimized via simulation data delivers greater propulsive force.