Investigating the Behavior of the Mooring System for a Conceptual Design of a Spar Floating Wind Turbine under Survival Conditions

In this paper, selecting of an appropriate mooring system for spar platform of a wind turbine consisting of chain–cable–chain is investigated based on a meta-heuristic method. The purpose is to investigate the hydrodynamic behavior of the structure and the mooring system in a normal and damaged conditions. ANSYS-AQWA software is applied to hydrodynamics analysis and the numerical results were first verified by experimental results. According to the characteristics of the experimental mooring system and designed stiffness in the desired depth of the sea, an appropriate chain is selected for the prototype model and then by investigating the changes applied to it and replacing a chain mooring system with a mooring system including chain–cable–chain, the survival behavior of the structure and mooring system evaluated for the 100-years return period, considering one of the mooring line disconnection. According to the controlling role of the initial chain connected to the structure, it was also observed that the decreasing the length of the initial chain and increasing the anchor chain length, the tension as well as the amplitude of the structural movements in the degrees of surge, heave and pitch increases.