Numerical analyses of nonlinear wave loads on an offshore wind turbine monopile
<p style="text-align:justify;"> Highly nonlinear extreme waves are the major, often the dominant, environmental load on offshore wind turbines. The higher-order ‘ringing’ loads associated with the nonlinear waves can cause unexpected resonance of the monopile. Hydrodynamic analysis...
| Main Authors: | , , , |
|---|---|
| Format: | Conference item |
| Published: |
American Society of Mechanical Engineers
2019
|
| _version_ | 1826287956341555200 |
|---|---|
| author | Adcock, T Feng, X Willden, R Zhou, B |
| author_facet | Adcock, T Feng, X Willden, R Zhou, B |
| author_sort | Adcock, T |
| collection | OXFORD |
| description | <p style="text-align:justify;"> Highly nonlinear extreme waves are the major, often the dominant, environmental load on offshore wind turbines. The higher-order ‘ringing’ loads associated with the nonlinear waves can cause unexpected resonance of the monopile. Hydrodynamic analysis of these harmonic loads remains a challenge due to the difficulty in extracting the bound harmonics from the force spectrum in an extreme wave event. A phase manipulation approach (four-phase combination) has been recently demonstrated to be able to separate the higher harmonic components of the wave loads in tank tests. In this work, we employ a fully nonlinear potential flow based Numerical Wave Tank (NWT) to simulate the wave diffraction by a fixed vertical column. We present a detailed study of our checks on the numerical accuracy of our model. Phase control is implemented for the wavemaker to manipulate the phase of each wave component. Focused wave groups are generated to represent the incoming extreme waves. With the four-phase decomposition, the higher harmonics of the wave loads are shown to be clearly separated. Comparisons with the existing test results show fairly good agreement at higher harmonics. The structure of the harmonic forces and moments are analysed and we reconstruct the higher harmonics based on the Stokes expansion assumption using the linear force. In addition, the effects of wave steepness on the harmonic components are discussed. </p> |
| first_indexed | 2024-03-07T02:06:27Z |
| format | Conference item |
| id | oxford-uuid:9f2c07cb-46c4-42cd-89a7-cc0ed852f444 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T02:06:27Z |
| publishDate | 2019 |
| publisher | American Society of Mechanical Engineers |
| record_format | dspace |
| spelling | oxford-uuid:9f2c07cb-46c4-42cd-89a7-cc0ed852f4442022-03-27T00:55:21ZNumerical analyses of nonlinear wave loads on an offshore wind turbine monopileConference itemhttp://purl.org/coar/resource_type/c_5794uuid:9f2c07cb-46c4-42cd-89a7-cc0ed852f444Symplectic Elements at OxfordAmerican Society of Mechanical Engineers2019Adcock, TFeng, XWillden, RZhou, B <p style="text-align:justify;"> Highly nonlinear extreme waves are the major, often the dominant, environmental load on offshore wind turbines. The higher-order ‘ringing’ loads associated with the nonlinear waves can cause unexpected resonance of the monopile. Hydrodynamic analysis of these harmonic loads remains a challenge due to the difficulty in extracting the bound harmonics from the force spectrum in an extreme wave event. A phase manipulation approach (four-phase combination) has been recently demonstrated to be able to separate the higher harmonic components of the wave loads in tank tests. In this work, we employ a fully nonlinear potential flow based Numerical Wave Tank (NWT) to simulate the wave diffraction by a fixed vertical column. We present a detailed study of our checks on the numerical accuracy of our model. Phase control is implemented for the wavemaker to manipulate the phase of each wave component. Focused wave groups are generated to represent the incoming extreme waves. With the four-phase decomposition, the higher harmonics of the wave loads are shown to be clearly separated. Comparisons with the existing test results show fairly good agreement at higher harmonics. The structure of the harmonic forces and moments are analysed and we reconstruct the higher harmonics based on the Stokes expansion assumption using the linear force. In addition, the effects of wave steepness on the harmonic components are discussed. </p> |
| spellingShingle | Adcock, T Feng, X Willden, R Zhou, B Numerical analyses of nonlinear wave loads on an offshore wind turbine monopile |
| title | Numerical analyses of nonlinear wave loads on an offshore wind turbine monopile |
| title_full | Numerical analyses of nonlinear wave loads on an offshore wind turbine monopile |
| title_fullStr | Numerical analyses of nonlinear wave loads on an offshore wind turbine monopile |
| title_full_unstemmed | Numerical analyses of nonlinear wave loads on an offshore wind turbine monopile |
| title_short | Numerical analyses of nonlinear wave loads on an offshore wind turbine monopile |
| title_sort | numerical analyses of nonlinear wave loads on an offshore wind turbine monopile |
| work_keys_str_mv | AT adcockt numericalanalysesofnonlinearwaveloadsonanoffshorewindturbinemonopile AT fengx numericalanalysesofnonlinearwaveloadsonanoffshorewindturbinemonopile AT willdenr numericalanalysesofnonlinearwaveloadsonanoffshorewindturbinemonopile AT zhoub numericalanalysesofnonlinearwaveloadsonanoffshorewindturbinemonopile |