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Parametric Assessment of Hull Geometry Effects on the Coupled Dynamics of Semi-Submersible Floating Wind Turbines
Mohammad Javad Eslahi1 , Saeid Kazemi *1 , Mojtaba Ezam2 , Madjid Ghodsi hassanabad3
1- Department of Civil Engineering, SRBIAU
2- Department of Physics Oceanography, SRBIAU
3- Department of Mechanical Engineering, SRBIAU
Abstract:   (417 Views)
This study presents a systematic investigation into the influence of geometric parameters and structural characteristics on the dynamic response of a semi-submersible platform supporting a floating wind turbine, with an emphasis on identifying stable performance regimes rather than determining a single optimal configuration. The analyses initiated with preliminary linear evaluations and were subsequently complemented by nonlinear time-domain simulations. A comparison of these approaches demonstrates that while the linear model is useful for identifying general response trends, it fails to fully capture oscillation amplitudes or the coupling intensity among degrees of freedom, particularly under hydrodynamic nonlinearities and mooring system effects. Consequently, a realistic assessment of system behavior necessitates nonlinear analysis. The investigation focused primarily on surge, heave, and pitch motions, as sway, roll, and yaw contributed minimally to the global response. Results indicate that the vertical and rotational motions of the platform are governed not only by the heave plate geometry but also by its interaction with the offset column arrangement. Variations in heave plate diameter and thickness, in conjunction with the geometric configuration of the offset columns, alter the dynamic response by modifying the added mass, hydrodynamic damping, and the relative positions of the centers of gravity and buoyancy. Within the examined range, heave plate diameters of 24–30 m and thicknesses equivalent to 7–10.5% of the offset column height produced more stable responses without shifting natural frequencies toward resonance. Specifically, a diameter of approximately 28.5 m and a thickness of around 8% yielded balanced surge, heave, and pitch responses. However, comparable performance across adjacent configurations suggests a robust design envelope rather than a single unique optimum. Overall, the findings highlight the utility of evaluating geometric parameters within an integrated framework to elucidate the relationships between platform geometry, hydrodynamic coefficients, and the coupled dynamic response.
Keywords: Floating offshore wind Turbines, Coupled Dynamics, Hull Form Effects, Time-Domain Solution Method, Response Amplitude Operation
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Highlights
  1. A systematic parametric numerical study was conducted to examine the coupled dynamics of a semi-submersible floating wind turbine platform.
  2. A two-stage workflow combining linear screening and nonlinear time-domain simulations was employed to provide a more realistic response assessment.
  3. Surge, heave, and pitch were identified as the dominant motions, while sway, roll, and yaw remained negligible in the investigated cases.
  4. Platform performance was governed by interacting design variables, including heave-plate geometry, offset-column configuration, mass distribution, and mooring characteristics.
  5. The results indicate a favorable and stable design range, supporting a robust design envelope rather than a single unique optimum.

 
Type of Study: Research Paper | Subject: Offshore Hydrodynamic
Received: 2026/02/5 | Accepted: 2026/06/8
Audio file of the article abstract [MP3 3924 KB]  (16 Download)
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