Real-Time Hybrid Model Testing of a Semi-Submersible 10MW Floating Wind Turbine and Advances in the Test Method

Thys, Maxime; Chabaud, Valentin; Sauder, Thomas; Eliassen, Lene; Sæther, Lars Ove; Magnussen, O. M.

doi:10.1115/iowtc2018-1081

Cited by 14 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They conclude that it is reasonable to exclude second‐order hydrodynamics for floating wind turbines in production because the aerodynamic thrust dominates the low‐frequency dynamics but they should be included when the rotor thrust is lower such as in parked/idling condition. More recently, experimental results of a floating wind turbine using a hybrid approach with wires to introduce the rotor thrust have been presented in Thys et al, although the measurements are not compared with numerical simulations and second‐order hydrodynamic effects are not discussed. They show that the wind turbulence plays a role on the low‐frequency dynamics of the platform.…”

Section: Introductionmentioning

confidence: 89%

Low‐frequency dynamics of a floating wind turbine in wave tank–scaled experiments with SiL hybrid method

2019

View full text Add to dashboard Cite

The design of floating wind turbines needs the validation of numerical models against measurements obtained from experiments that accurately represent the system dynamics. This requires solving the conflict in the scaling of the hydrodynamic and aerodynamic forces that arises in tests with wind and waves. To sort out this conflict, we propose a hybrid testing method that uses a ducted fan to replace the rotor and introduce a force representing the aerodynamic thrust. The force is obtained from a simulation of the rotor coupled in real time with the measured platform displacements at the basin. This method is applied on a test campaign of a semisubmersible wind turbine with a scale factor of 1/45. The experimental data are compared with numerical computations using linear and non-linear hydrodynamic models. Pitch decays in constant wind show a good agreement with computations, demonstrating that the hybrid testing method correctly introduces the aerodynamic damping. Test cases with constant wind and irregular waves show better agreement with the simulations in the power spectral density's (PSD's) low-frequency region when non-linear hydrodynamics are computed. In cases with turbulent wind at rated wind speed, the low-frequency platform motions are dominated by the wind, hiding the differences from hydrodynamic non-linearities. In these conditions, the agreement between experiments using the proposed hybrid method and computations is good in all the frequency range both for the linear and the non-linear hydrodynamic models. Conversely, for turbulent winds producing lower rotor thrust, non-linear hydrodynamics are relevant for the simulation of the low-frequency system dynamics.

show abstract

Section: Introductionmentioning

confidence: 89%

Low‐frequency dynamics of a floating wind turbine in wave tank–scaled experiments with SiL hybrid method

2019

View full text Add to dashboard Cite

show abstract

“…Some of the main properties are collected in Tab. 1. sintef.no/en/ocean) in 2018, is described in detail in Thys et al [1,30]. The instrumentation relevant to this study includes:…”

Section: The Case Studymentioning

confidence: 99%

“…• Force transducers to record mooring line tension at the upper end (fairlead) of each mooring line. The pre-tension was measured once at the start of the test campaign, and deviations in the four lines between -6.82% and -9.46% when compared to the target are reported in [1]. For each test, the force sensors were zeroed before the test and the pre-tension was added afterwards.…”

Section: The Case Studymentioning

confidence: 99%

“…The aim of the present paper is to numerically reproduce the slow-drift response observed in physical tests, by combining both viscous and inviscid slow-drift forcing with a simplified damping model, suitable for efficient solution of the re-sponse. We further investigate the applicability of Operational Modal Analysis to extract damping levels from the physical model tests of a semi-submersible floating wind turbine in operational sea states of Thys et al [1].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reproduction of slow-drift motions of a floating wind turbine using second-order hydrodynamics and Operational Modal Analysis

Pegalajar‐Jurado

Bredmose

2019

Marine Structures

View full text Add to dashboard Cite

Slow-drift forcing and damping are important for an accurate reproduction of the low-frequency motion of floating offshore wind turbines. In this study we present a numerical model that includes both inviscid slow-drift forcing through full quadratic transfer functions (QTFs) and viscous forcing. To accommodate a linear damping matrix that represents all the damping effects on the floater, the classical Morison formulation of the drag forcing with relative velocity is simplified into a pure forcing term and a linear constant damping term. The frequency-dependent radiation properties are also replaced by constant matrices. We investigate the application of Operational Modal Analysis (OMA) to estimate the damping ratios from the test data, and also pursue a calibration method where the linear damping is calibrated in the modal space and subsequently transformed back to the physical space. The model is compared to wave basin data for four environmental conditions including the 50-year sea state. The damping ratios estimated with OMA generally increase with the sea state. The measured response can be generally well reproduced by the model when the damping is calibrated for each sea state. Due to the neglection of firstorder motion effects in the applied QTFs and to the damping introduced by the mooring lines, however, the surge response is underpredicted for the severe sea states, and the yaw motion is always underpredicted. The commonly used approach where the damping is calibrated to the decay tests is found to provide less accurate results than the approach of calibrating the modal damping ratios

show abstract

“…Sauder et al (2016) presented a RTHS testing method (ReaTHM) of a FWT and discussed possible error sources and their quantification. The same RTHS method later was applied in testing a 10-MW FWT (Thys et al, 2018). In these wave basin RTHS tests, the numerical component is the aerodynamic portion of the FWT simulated by a computer model, and the physical component is the Froude scaled floating structure including the tower.…”

Section: Introductionmentioning

confidence: 99%

Conceptual Study of a Real-Time Hybrid Simulation Framework for Monopile Offshore Wind Turbines Under Wind and Wave Loads

Song

Sun

Zuo

et al. 2020

Front. Built Environ.

View full text Add to dashboard Cite

As an attractive renewable energy source, offshore wind plants are becoming increasingly popular for energy production. However, the performance assessment of offshore wind turbine (OWT) structure is a challenging task due to the combined wind-wave loading and difficulties in reproducing such loading conditions in laboratory. Real-time hybrid simulation (RTHS), combining physical testing and numerical simulation in real-time, offers a new venue to study the structural behavior of OWTs. It overcomes the scaling incompatibilities in OWT scaled model testing by replacing the rotor components with an actuation system, driven by an aerodynamic simulation tool running in real-time. In this study, a RTHS framework for monopile OWTs is proposed. A set of sensitivity analyses is carried out to evaluate the feasibility of this RTHS framework and determine possible tolerances on its design. By simulating different scaling laws and possible error contributors (delays and noises) in the proposed framework, the sensitivity of the OWT responses to these parameters are quantified. An example using a National Renewable Energy Lab (NREL) 5-MW reference OWT system at 1:25 scale is simulated in this study to demonstrate the proposed RTHS framework and sensitivity analyses. Three different scaling laws are considered. The sensitivity results show that the delays in the RTHS framework significantly impact the performance on the response evaluation, higher than the impact of noises. The proposed framework and sensitivity analyses presented in this study provides important information for future implementation and further development of the RTHS technology for similar marine structures.

show abstract

Real-Time Hybrid Model Testing of a Semi-Submersible 10MW Floating Wind Turbine and Advances in the Test Method

Cited by 14 publications

References 0 publications

Low‐frequency dynamics of a floating wind turbine in wave tank–scaled experiments with SiL hybrid method

Low‐frequency dynamics of a floating wind turbine in wave tank–scaled experiments with SiL hybrid method

Reproduction of slow-drift motions of a floating wind turbine using second-order hydrodynamics and Operational Modal Analysis

Conceptual Study of a Real-Time Hybrid Simulation Framework for Monopile Offshore Wind Turbines Under Wind and Wave Loads

Contact Info

Product

Resources

About