scholarly journals Comparisons of dynamical characteristics of a 5 MW floating wind turbine supported by a spar-buoy and a semi-submersible using model testing methods

2018 ◽  
Vol 10 (5) ◽  
pp. 053311 ◽  
Author(s):  
Jiahao Chen ◽  
Zhiqiang Hu ◽  
Fei Duan
Author(s):  
Michael Borg ◽  
Anthony Viselli ◽  
Christopher K. Allen ◽  
Matthew Fowler ◽  
Christoffer Sigshøj ◽  
...  

Abstract As part of the process of deploying new floating offshore wind turbines, scale model testing is carried out to de-risk and verify the design of novel foundation concepts. This paper describes the testing of a 1:43 Froude-scaled model of the TetraSpar Demo floating wind turbine prototype that shall be installed at the Metcentre test facility, Norway. The TetraSpar floating foundation concept consists of a floater tetrahedral structure comprising of braces connected together through pinned connections, and a triangular keel structure suspended below the floater by six suspension lines. A description of the experimental setup and program at the Alfond W2 Ocean Engineering Lab at University of Maine is given. The objective of the test campaign was to validate the initial design, and contribute to the development of the final demonstrator design and numerical models. The nonlinear hydrodynamic characteristics of the design are illustrated experimentally and the keel suspension system is shown to satisfy design criteria.


Author(s):  
Heather R. Martin ◽  
Richard W. Kimball ◽  
Anthony M. Viselli ◽  
Andrew J. Goupee

Scale model wave basin testing is often employed in the development and validation of large scale offshore vessels and structures by the oil and gas, military and marine industries. A basin model test requires less time, resources and risk than a full scale test while providing real and accurate data for model validation. As the development of floating wind turbine technology progresses in order to capture the vast deepwater wind energy resource, it is clear that model testing will be essential for the economical and efficient advancement of this technology. However, the scale model testing of floating wind turbines requires one to accurately simulate the wind and wave environments, structural flexibility and wind turbine aerodynamics, and thus requires a comprehensive scaling methodology. This paper presents a unified methodology for Froude scale testing of floating wind turbines under combined wind and wave loading. First, an overview of the scaling relationships employed for the environment, floater and wind turbine are presented. Afterward, a discussion is presented concerning suggested methods for manufacturing a high-quality, low turbulence Froude scale wind environment in a wave basin to facilitate simultaneous application of wind and waves to the model. Subsequently, the difficulties of scaling the highly Reynolds number-dependent wind turbine aerodynamics is presented in addition to methods for tailoring the turbine and wind characteristics to best emulate the full scale condition. Lastly, the scaling methodology is demonstrated using results from 1/50th scale floating wind turbine testing performed at MARIN’s (Maritime Research Institute Netherlands) Offshore Basin which tested the 126 m rotor diameter NREL (National Renewable Energy Lab) horizontal axis wind turbine atop three floating platforms: a tension-leg platform, a spar-buoy and a semi-submersible. The results demonstrate the methodology’s ability to adequately simulate full scale global response of floating wind turbine systems.


Author(s):  
Erik-Jan de Ridder ◽  
William Otto ◽  
Gert-Jan Zondervan ◽  
Fons Huijs ◽  
Guilherme Vaz

In the last years MARIN has been involved in an increasing number of projects for the offshore wind industry. New techniques in model testing and numerical simulations have been developed in this field. In this paper the development of a scaled-down wind turbine operating on a floating offshore platform, similar to the well-known 5MW NREL wind turbine is discussed. To simulate the response of a floating wind turbine correctly it is important that the environmental loads due to wind, waves and current are in line with full scale. For dynamic similarity on model scale, Froude scaling laws are used successfully in the Offshore industry for the underwater loads. To be consistent with the underwater loads, the winds loads have to be scaled according to Froude as well. Previous model tests described by Robertson et al [1] showed that a geometrically-scaled turbine generated a lower thrust and power coefficient with a Froude-scaled wind velocity due to the strong Reynolds scale effects on the flow. To improve future model testing, a new scaling method for the wind turbine blades was developed originally by University of Maine, and here improved and applied. In this methodology, the objective is to obtain power and thrust coefficients which are similar to the full-scale turbine in Froude-scaled wind. This is obtained by changing the geometry of the blades in order to provide thrust equality between model and full scale, and can therefore be considered as a “performance scaling”. This method was then used to design and construct a new MARIN Stock Wind Turbine (MSWT) based on the NREL 5MW wind turbine blade, including an active blade pitch control to simulate different blade pitch control systems. MARIN’s high-quality wind setup in combination with the new model scale stock wind turbine was used for testing the GustoMSC Tri-Floater semi-submersible as presented in Figure 1, including an ECN active blade pitch control algorithm. From the model tests it was concluded that the measured thrust versus wind velocity characteristics of the new MSWT were in line with the full scale prediction and with CFD (Computational Fluid Dynamics) results.


Author(s):  
Heather R. Martin ◽  
Richard W. Kimball ◽  
Anthony M. Viselli ◽  
Andrew J. Goupee

Scale-model wave basin testing is often employed in the development and validation of large-scale offshore vessels and structures by the oil and gas, military, and marine industries. A basin-model test requires less time, resources, and risk than a full-scale test, while providing real and accurate data for numerical simulator validation. As the development of floating wind turbine technology progresses in order to capture the vast deep-water wind energy resource, it is clear that model testing will be essential for the economical and efficient advancement of this technology. However, the scale model testing of floating wind turbines requires accurate simulation of the wind and wave environments, structural flexibility, and wind turbine aerodynamics and thus requires a comprehensive scaling methodology. This paper presents a unified methodology for Froude scale model testing of floating wind turbines under combined wind and wave loading. First, an overview of the scaling relationships employed for the environment, floater, and wind turbine are presented. Afterward, a discussion is presented concerning suggested methods for manufacturing a high-quality, low-turbulence Froude scale wind environment in a wave basin to facilitate simultaneous application of wind and waves to the model. Subsequently, the difficulties of scaling the highly Reynolds number–dependent wind turbine aerodynamics is presented in addition to methods for tailoring the turbine and wind characteristics to best emulate the full-scale condition. Lastly, the scaling methodology is demonstrated using results from 1/50th-scale floating wind turbine testing performed at the Maritime Research Institute Netherlands (MARIN) Offshore Basin. The model test campaign investigated the response of the 126 -m rotor diameter National Renewable Energy Lab (NREL) horizontal axis wind turbine atop three floating platforms: a tension-leg platform, a spar-buoy, and a semisubmersible. The results highlight the methodology's strengths and weaknesses for simulating full-scale global response of floating wind turbine systems.


2021 ◽  
Vol 78 ◽  
pp. 102970
Author(s):  
B. Wiegard ◽  
M. König ◽  
J. Lund ◽  
L. Radtke ◽  
S. Netzband ◽  
...  

2021 ◽  
Vol 221 ◽  
pp. 108528
Author(s):  
Shengwen Xu ◽  
Motohiko Murai ◽  
Xuefeng Wang ◽  
Kensaku Takahashi

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 248
Author(s):  
Lorenzo Cottura ◽  
Riccardo Caradonna ◽  
Alberto Ghigo ◽  
Riccardo Novo ◽  
Giovanni Bracco ◽  
...  

Wind power is emerging as one of the most sustainable and low-cost options for energy production. Far-offshore floating wind turbines are attractive in view of exploiting high wind availability sites while minimizing environmental and landscape impact. In the last few years, some offshore floating wind farms were deployed in Northern Europe for technology validation, with very promising results. At present time, however, no offshore wind farm installations have been developed in the Mediterranean Sea. The aim of this work is to comprehensively model an offshore floating wind turbine and examine the behavior resulting from a wide spectrum of sea and wind states typical of the Mediterranean Sea. The flexible and accessible in-house model developed for this purpose is compared with the reference model FAST v8.16 for verifying its reliability. Then, a simulation campaign is carried out to estimate the wind turbine LCOE (Levelized Cost of Energy). Based on this, the best substructure is chosen and the convenience of the investment is evaluated.


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