RT Journal Article
T1 Accelerated second-order hydrodynamic load calculation on semi-submersible floaters
A1 Alonso Reig, Maria
A1 Pegalajar-Jurado, Antonio
A1 Mendikoa, Iñigo
A1 Petuya, Victor
A1 Bredmose, Henrik
AB A rapid method for calculation of second-order hydrodynamic wave loads on semi-submersible platforms is developed and validated against radiation–diffraction theory. The method is based on slender-body theory and builds on modal truncation of the quadratic transfer function (QTF). The semi-submersible floater is split into individual members and the existing theory for vertical cylindrical columns is extended to include the heave force. Further expressions for the surge, heave and pitch load on the horizontal pontoons are derived and implemented. The accuracy of the method is assessed by comparison to radiation–diffraction results using the Pinkster approximation. We find that the slender-body approximation for the column surge force is most accurate for small values of the diameter-to-draft ratio. For the three sea states considered, this error is below 10% for diameter-to-draft ratios less than 0.2. Error analysis is provided for the column heave and pitch and the pontoon loads. For all members, application of 128 modes in the QTF approximation is found sufficient to accurately represent the full slender-body QTF solution. Next, the first- and second-order loads on the full floater under different sea state conditions are compared to radiation–diffraction theory. With 128 modes, the second-order loads are obtained 2500 times faster than with conventional approaches with error levels of 22% for surge, 10% for pitch and zero error for heave. The surge error is discussed and linked to the small draft of the columns. The numerical efficiency of the method allows the consideration of second-order loads in the first stages of the design and optimisation of semi-submersible floaters.
SN 0951-8339
YR 2023
FD 2023-07
LK https://hdl.handle.net/11556/5076
UL https://hdl.handle.net/11556/5076
LA eng
NO Alonso Reig , M , Pegalajar-Jurado , A , Mendikoa , I , Petuya , V & Bredmose , H 2023 , ' Accelerated second-order hydrodynamic load calculation on semi-submersible floaters ' , Marine Structures , vol. 90 , 103430 . https://doi.org/10.1016/j.marstruc.2023.103430
NO Publisher Copyright: © 2023 The Authors
NO The authors wish to acknowledge the financial support received from the Spanish Government through the Ministerio de Ciencia e Innovación (Project PID2020-116176GB-I00 ) financed by MCIN/AEI/ 10.13039/501100011033 and the support for the research group through Project IT1480-22 provided by the Departamento de Educación from the Regional Basque Government, Spain ; and by Euskampus Fundazioa . The work of A. Pegalajar-Jurado and H. Bredmose was supported by Innovation Fund Denmark , grant nr. 8055-00075B , as part of the FloatStep project. This support is gratefully acknowledged. This work was funded by the Basque Government through the BIKAINTEK PhD support program [grant number 48-AF-W2-2019-00011]. The authors wish to acknowledge the financial support received from the Spanish Government through the Ministerio de Ciencia e Innovación (Project PID2020-116176GB-I00) financed by MCIN/AEI/ 10.13039/501100011033 and the support for the research group through Project IT1480-22 provided by the Departamento de Educación from the Regional Basque Government, Spain; and by Euskampus Fundazioa. The work of A. Pegalajar-Jurado and H. Bredmose was supported by Innovation Fund Denmark, grant nr. 8055-00075B, as part of the FloatStep project. This support is gratefully acknowledged. The authors acknowledge TECNALIA and SENER for their support to the PhD thesis of María Alonso Reig. This work was funded by the Basque Government through the BIKAINTEK PhD support program [grant number 48-AF-W2-2019-00011 ].
DS TECNALIA Publications
RD 29 sept 2024