Investigation on Seakeeping of WTIVs Considering the Effect of Leg-Spudcan Well

Aiming at the limited applicability of traditional empirical formulas in roll prediction for offshore wind turbine installation vessels (WTIVs), this study proposes a collaborative verification method that integrates model tests with Computational Fluid Dynamics (CFD) simulations. This approach reveals the influence mechanism of the fluid trapped in the leg-spudcan well region on the roll period and damping, facilitating high-precision prediction. A numerical model of the WTIV in a jack-up operating condition was established, and a CFD method based on the RANS equations was employed alongside experimental data for synergistic analysis. The results demonstrate that the fluid in the leg-spudcan well generates a significant additional moment of inertia, which reduces the natural roll period by approximately 7% and increases the damping coefficient by approximately 58%. Furthermore, an increase in leg length leads to a linear increase in damping and a linear decrease in the roll period. The motion response transfer functions derived from tests and the motion response errors of key structures in irregular waves are generally less than 10%. On this basis, a motion response conversion method applicable to any location on the entire ship is derived, providing a reliable numerical analysis tool for WTIV seakeeping evaluation and operational window assessment.