Model test investigation of a spar floating wind turbine

Wind power has great potential because of its clean and renewable production compared to the traditional power. Most of the present researches for floating wind turbine rely on the hydro-aero-elastic-servo simulation codes and have not been exhaustively validated yet. Thus, model tests are needed and make sense for its high credibility to master the kinetic characters of floating offshore structures. The characters of kinetic responses of the spar-type wind turbine are investigated through model test research technique. This paper describes the methodology for wind/wave model test that carried out at Deepwater Offshore Basin in Shanghai Jiao Tong University at a scale of 1:50. A Spar-type floater was selected to support the wind turbine in this test and the model blade was geometrically scaled down from the original NREL 5 MW reference wind turbine blade. The detail of the scaled model of wind turbine and the floating supporter, the test set-up configuration, the mooring system, the high-quality wind generator that can create required homogeneous and low turbulence wind, and the instrumentations to capture loads, accelerations and 6 DOF motions are described in detail, respectively. The isolated wind/wave effects and the integrated wind-wave effects on the floating wind turbine are analyzed, according to the test results.

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Model Test of a 1:8-Scale Floating Wind Turbine Offshore in the Gulf of Maine1

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.4030381 ◽

2015 ◽

Vol 137 (4) ◽

Cited By ~ 21

Author(s):

Anthony M. Viselli ◽

Andrew J. Goupee ◽

Habib J. Dagher

Keyword(s):

Wind Turbine ◽

Physical Model ◽

Test Data ◽

Model Test ◽

Test Site ◽

Full Scale ◽

Scale Construction ◽

Offshore Wind ◽

Testing Effort ◽

Floating Wind Turbine

A new floating wind turbine platform design called VolturnUS developed by the University of Maine uses innovations in materials, construction, and deployment technologies such as a concrete semisubmersible hull and a composite tower to reduce the costs of offshore wind. These novel characteristics require research and development prior to full-scale construction. This paper presents a unique offshore model testing effort aimed at derisking full-scale commercial projects by providing scaled global motion data, allowing for testing of materials representative of the full-scale system, and demonstrating full-scale construction and deployment methods. A 1:8-scale model of a 6 MW semisubmersible floating wind turbine was deployed offshore Castine, ME, in June 2013. The model includes a fully operational commercial 20 kW wind turbine and was the first grid-connected offshore wind turbine in the U.S. The testing effort includes careful selection of the offshore test site, the commercial wind turbine that produces the correct aerodynamic thrust given the wind conditions at the test site, scaling methods, model design, and construction. A suitable test site was identified that produced scaled design load cases (DLCs) prescribed by the American Bureau of Shipping (ABS) Guide for Building and Classing Floating Offshore Wind Turbines. A turbine with a small rotor diameter was selected because it produces the correct thrust load given the wind conditions at the test site. Some representative data from the test are provided in this paper. Model test data are compared directly to full-scale design predictions made using coupled aeroelastic/hydrodynamic software. Scaled VolturnUS performance data during DLCs show excellent agreement with full-scale predictive models. Model test data are also compared directly without scaling against a numerical representation of the 1:8-scale physical model for the purposes of numerical code validation. The numerical model results compare favorably with data collected from the physical model.

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Model test research of a semisubmersible floating wind turbine with an improved deficient thrust force correction approach

Renewable Energy ◽

10.1016/j.renene.2017.12.019 ◽

2018 ◽

Vol 119 ◽

pp. 95-105 ◽

Cited By ~ 10

Author(s):

Liang Li ◽

Yan Gao ◽

Zhiqiang Hu ◽

Zhiming Yuan ◽

Sandy Day ◽

...

Keyword(s):

Wind Turbine ◽

Model Test ◽

Thrust Force ◽

Floating Wind Turbine

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Model Test Data Correlations With Fully Coupled Hull/Mooring Analysis for a Floating Wind Turbine on a Semi-Submersible Platform

Volume 9B: Ocean Renewable Energy ◽

10.1115/omae2014-24254 ◽

2014 ◽

Cited By ~ 7

Author(s):

Bonjun Koo ◽

Andrew J. Goupee ◽

Kostas Lambrakos ◽

Ho-Joon Lim

Keyword(s):

Wind Turbine ◽

Model Test ◽

Model Tests ◽

Test Results ◽

Scaled Model ◽

Floating Wind Turbine ◽

Mooring Dynamics ◽

Set Up ◽

Fully Coupled ◽

Turbine Model

The DeepCwind floating wind turbine model tests were performed at MARIN (Maritime Research Institute Netherlands) with a model set-up corresponding to a 1:50 Froude scaling. In the model tests, the wind turbine was a scaled model of the National Renewable Energy Lab (NREL) 5MW, horizontal axis reference wind turbine supported by three different generic floating platforms: a spar, a semi-submersible and a tension-leg platform (TLP) (Ref. [1] and [2]). This paper presents validation of the MLTSIM-FAST [3] code with DeepCwind semi-submersible wind turbine model test results. In this integrated program, the turbine tower and rotor dynamics are simulated by the subroutines of FAST [4], and the hydrodynamic loads and mooring system dynamics are simulated by the subroutines of MLTSIM. In this study, fully coupled hull/mooring dynamics and second-order difference-frequency response are included in MLTSIM-FAST. The analysis results are systematically compared with model test results and show good agreement.

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Model Test of a 1:8 Scale Floating Wind Turbine Offshore in the Gulf of Maine

Volume 9A: Ocean Renewable Energy ◽

10.1115/omae2014-23639 ◽

2014 ◽

Cited By ~ 4

Author(s):

Anthony M. Viselli ◽

Andrew J. Goupee ◽

Habib J. Dagher

Keyword(s):

Wind Turbine ◽

Physical Model ◽

Test Data ◽

Model Test ◽

Test Site ◽

Full Scale ◽

Scale Construction ◽

Offshore Wind ◽

Testing Effort ◽

Floating Wind Turbine

A new floating wind turbine platform design called VolturnUS developed by the University of Maine uses innovations in materials, construction, and deployment technologies such as a concrete semi-submersible hull and a composite tower to reduce the costs of offshore wind. These novel characteristics require research and development prior to full-scale construction. This paper presents a unique offshore model testing effort aimed at de-risking full-scale commercial projects by providing properly scaled global motion data, allowing for implementation of full-scale structural materials, and demonstrating full-scale construction and deployment methods. The model is a 1:8-scale model of a 6MW semi-submersible floating wind turbine and was deployed offshore Castine, Maine, USA in June, 2013. The model uses a fully operational turbine and was the first grid connected offshore wind turbine in the Americas. The testing effort includes careful treatment of the offshore test site, scaling methods, model design, and construction. A suitable test site was identified that provides the correct proportions of wind and wave loading in order to simulate design load cases prescribed by the American Bureau of Shipping Standard for Building and Classing Floating Offshore Wind Turbines. Sample model test data is provided. Model test data is directly compared to full-scale design predictions made using coupled aeroelastic/ hydrodynamic software. VolturnUS performance data from scaled extreme sea states show excellent agreement with predictive models. Model test data are also compared to a numerical representation of the physical model for the purposes of numerical code validation. The numerical model results compare very favorably with data collected from the physical model.

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Methodology for Wind/Wave Basin Testing of Floating Offshore Wind Turbines

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.4025030 ◽

2014 ◽

Vol 136 (2) ◽

Cited By ~ 30

Author(s):

Heather R. Martin ◽

Richard W. Kimball ◽

Anthony M. Viselli ◽

Andrew J. Goupee

Keyword(s):

Wind Turbine ◽

Model Test ◽

Wind Turbines ◽

Model Testing ◽

Full Scale ◽

Scale Model ◽

Horizontal Axis Wind Turbine ◽

Wind Turbine Aerodynamics ◽

Floating Wind Turbine ◽

Wave Basin

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.

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Model Test of the STC Concept in Survival Modes

Volume 9A: Ocean Renewable Energy ◽

10.1115/omae2014-23213 ◽

2014 ◽

Cited By ~ 3

Author(s):

Ling Wan ◽

Zhen Gao ◽

Torgeir Moan

Keyword(s):

Wind Turbine ◽

Model Test ◽

Extreme Conditions ◽

Regular Wave ◽

Wave Load ◽

Large Wave ◽

Irregular Wave ◽

Floating Wind Turbine ◽

The Mean ◽

Wave Conditions

The STC (Spar Torus Combination) concept combines a Spar floating wind turbine and a torus-shaped heaving-body wave energy converter (WEC). Numerical simulation has shown positive synergy between the WEC and the Spar floating wind turbine in operational conditions. However, in extreme wind and wave conditions, it is challenging to maintain structural integrity, especially for the WEC. To ensure survivability of this concept in extreme conditions, three survival modes have been proposed. To investigate the performance of the STC in extreme conditions, model tests with a scale factor of 1:50 were carried out in the towing tank of MARINTEK, Norway. Two survival modes were tested. In both modes, the Torus WEC was fixed to the Spar. In the first mode, the Torus WEC is at the mean water surface, while in the second mode, the Torus WEC is fully submerged to a specified position. In the tests, 6 D.O.F rigid body motions, mooring line tensions, forces in 3 directions (X, Y and Z) between the Spar and Torus were measured, wind velocity and wind force were also measured by a sensor in front of the model and a load cell installed on the wind disc. In this paper, the model test set-up for the two survival modes are described, and then decay tests, regular wave tests and the statistical tests for wind only, irregular wave only and irregular wave plus wind are presented, compared and analyzed. In the mean water level survival mode, the Torus had a small draft and large water plane area, so slamming and green water were observed as expected. In addition, Mathieu instability phenomena were observed during the regular wave test. In some large wave conditions in the fully submerged mode, no severe wave load occurred. All the results are presented in model scale unless specified, for direct comparison with numerical simulations later.

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