Ocean Current Effects on Modified SPAR Wind Floaters: Implications for Motion and Load Management

This research examines the impact of flow-induced motion (FIM) on SPAR-type floating offshore wind turbine substructures under various uniform current conditions. Motivated by concerns over increased structural stress, reduced efficiency, and imbalanced mooring tensions, the study aims to optimize lower SPAR substructures for improved stability and efficiency. A combination of numerical simulations and experimental validation was used to analyze in-line and cross-flow motion characteristics, hydrodynamic properties, and mooring tension distribution. The configurations studied include the base, 3VP, 4VP, and 5VP models. Results show that the 4VP configuration offers superior stability, reduced oscillation, effective resonance suppression, and balanced mooring loads, particularly at low to medium current angles (0°–45°). In contrast, the Base model was highly susceptible to resonance and exhibited significant oscillation and uneven load distribution. While the 5VP configuration shows potential under high reduced velocities and steep angles, further optimization is needed. This research highlights the importance of enhancing vertical plates (VP) to mitigate FIM effects and ensure structural integrity in evolving SPAR designs for offshore renewable energy. Future studies will explore multi-directional and extreme current scenarios.