Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load Analyses

The purpose of this study is to analyze the differences in motion response performances according to the design variables of semi-submersible substructures supporting floating offshore wind turbines (FOWTs) and propose an improved design. The specifications of the IEA 15 MW reference semi-submersibl...

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Main Authors: Soo Bin Lee, Joonmo Choung
Format: Article
Language:English
Published: The Korean Society of Ocean Engineers 2025-04-01
Series:한국해양공학회지
Subjects:
Online Access:https://doi.org/10.26748/KSOE.2025.003
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author Soo Bin Lee
Joonmo Choung
author_facet Soo Bin Lee
Joonmo Choung
author_sort Soo Bin Lee
collection DOAJ
description The purpose of this study is to analyze the differences in motion response performances according to the design variables of semi-submersible substructures supporting floating offshore wind turbines (FOWTs) and propose an improved design. The specifications of the IEA 15 MW reference semi-submersible FOWT were used for this study. Draft, circumradius, main column diameter, and pontoon breadth were determined as dominant design variables that significantly affect the motion response of the substructure. A Python code was developed to automatically generate hundreds of analysis models. Motion responses were derived through frequency domain load analyses. The responses were heave natural period, pitch angle, and acceleration at the rotor nacelle assembly (RNA) with 20 year-return period. Deeper drafts resulted in less development of RNA acceleration and pitch angle. The main column diameter had the greatest impact on the heave natural period. Main column diameter, pontoon breadth, and circumradius controlled the pitch angle response amplitude operator (RAO) and RNA acceleration RAO. The RNA acceleration did not show consistent trends with design variables due to resonance. With assumed weighting factors for each variable, the reference FOWT substructure was improved. The results are expected to make a significant contribution to improving the motion performance of FOWTs.
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institution Kabale University
issn 1225-0767
2287-6715
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publisher The Korean Society of Ocean Engineers
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series 한국해양공학회지
spelling doaj-art-90e8918dd64f4cb1a8e07a42cb58ed9b2025-08-20T03:53:39ZengThe Korean Society of Ocean Engineers한국해양공학회지1225-07672287-67152025-04-0139218920410.26748/KSOE.2025.003Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load AnalysesSoo Bin Lee0https://orcid.org/0009-0000-9754-7915Joonmo Choung1https://orcid.org/0000-0003-1407-9031Inha UniversityInha UniversityThe purpose of this study is to analyze the differences in motion response performances according to the design variables of semi-submersible substructures supporting floating offshore wind turbines (FOWTs) and propose an improved design. The specifications of the IEA 15 MW reference semi-submersible FOWT were used for this study. Draft, circumradius, main column diameter, and pontoon breadth were determined as dominant design variables that significantly affect the motion response of the substructure. A Python code was developed to automatically generate hundreds of analysis models. Motion responses were derived through frequency domain load analyses. The responses were heave natural period, pitch angle, and acceleration at the rotor nacelle assembly (RNA) with 20 year-return period. Deeper drafts resulted in less development of RNA acceleration and pitch angle. The main column diameter had the greatest impact on the heave natural period. Main column diameter, pontoon breadth, and circumradius controlled the pitch angle response amplitude operator (RAO) and RNA acceleration RAO. The RNA acceleration did not show consistent trends with design variables due to resonance. With assumed weighting factors for each variable, the reference FOWT substructure was improved. The results are expected to make a significant contribution to improving the motion performance of FOWTs.https://doi.org/10.26748/KSOE.2025.003floating offshore wind turbinedominant design variablefrequency response analysisheave natural periodpitch anglerna acceleration
spellingShingle Soo Bin Lee
Joonmo Choung
Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load Analyses
한국해양공학회지
floating offshore wind turbine
dominant design variable
frequency response analysis
heave natural period
pitch angle
rna acceleration
title Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load Analyses
title_full Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load Analyses
title_fullStr Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load Analyses
title_full_unstemmed Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load Analyses
title_short Design Improvement of a Semi-submersible Floating Offshore Wind Turbines through Frequency-domain Load Analyses
title_sort design improvement of a semi submersible floating offshore wind turbines through frequency domain load analyses
topic floating offshore wind turbine
dominant design variable
frequency response analysis
heave natural period
pitch angle
rna acceleration
url https://doi.org/10.26748/KSOE.2025.003
work_keys_str_mv AT soobinlee designimprovementofasemisubmersiblefloatingoffshorewindturbinesthroughfrequencydomainloadanalyses
AT joonmochoung designimprovementofasemisubmersiblefloatingoffshorewindturbinesthroughfrequencydomainloadanalyses