Numerical investigation of motion control of a barge-type floating offshore wind turbine using a bidirectional tuned liquid damper and a horizontal skirt

초록

This study presents a numerical investigation of a passive motion-control strategy aimed at elucidating the hydrodynamic mechanisms governing pitch-dominated responses of barge-type floating offshore wind turbine (FOWT) platforms. The system consists of a square barge-type platform equipped with a bidirectional tuned liquid damper (BTLD) and an external horizontal skirt attached beneath the outer perimeter. A fully coupled time-domain computational fluid dynamics (CFD) model is employed to simulate the platform dynamic responses under wave excitation, with primary emphasis on pitch motion, while heave is examined as a secondary, frequency-dependent effect. The results under regular waves demonstrate that the BTLD significantly mitigates pitch motion relative to the bare platform through internal sloshing-induced dissipation. The addition of the horizontal skirt further enhances rotational suppression by modifying the near-field wave-structure interaction, although the heave response remains strongly period-dependent. Parametric investigations identify a design-tuned configuration near the natural pitch period of the platform, yielding the most pronounced motion reduction among the investigated cases. The combined BTLD-skirt system exhibits complementary control mechanisms, with internal liquid dynamics governing rotational damping and the external skirt reshaping hydrodynamic loading. To further evaluate robustness under realistic sea states, additional simulations were conducted under an irregular JONSWAP wave. The results confirm that the proposed passive-control configuration maintains effective pitch-mitigation performance under stochastic excitation, with amplitude-dependent trends consistent with the regular-wave analysis.

키워드