Numerical model validation for mooring systems: Method and application for wave energy converters

Harnois, Violette; Weller, Sam; Johanning, Lars; Thies, Philipp R.; Boulluec, Marc Le; Roux, Dominique; Soulé, V.; Ohana, Jérémy

doi:10.1016/j.renene.2014.10.063

Cited by 51 publications

(39 citation statements)

References 8 publications

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“…However, it is necessary to validate that the extremes found in the models resemble realistic values, for which experimental data are used. Model validation against experimental data has been done in [13] for a WEC and by several authors like, e.g., [14,15,22,23] for floating wind turbine platforms, mainly considering waves and not the coupled effect of wind and wave exposure.…”

Section: Design and Modeling Of Floating Structures With A Mooring Symentioning

confidence: 99%

“…The work in [13] presented a method that can be used, but the present study made a coarse sensitivity analysis to find values of linear damping in heave and pitch, which improves the model results for the regular tests. By adding 1000 kN m/s and 4000 kNm rad/s in respectively heave and pitch, the model showed better agreement with experiments.…”

Section: Optimized Modelmentioning

confidence: 99%

“…This allows for tuning of the model so that good agreement between experiments and the numerical model is achieved for the tested sea states, mooring layout and model geometry. For instance, [13] presents a methodology for optimization of the numerical model of a WEC, and a similar one is seen in, e.g., [14,15], which considers floating wind turbine platforms, aims to prove the validity of numerical models and tunes them to available experimental tests. For many early stage WECs, however, experimental data are not available, and there is a need for understanding the mooring system behavior prior to performing tests.…”

Section: Introductionmentioning

confidence: 99%

“…It is, therefore, essential to have a model that can be used in initial studies of the potential of different mooring layouts and materials, even without access to experimental data. Where studies like, e.g., [13][14][15] tune the model to fit the experimental results, the present paper tends to validate a numerical tool according to the definition of validation in [16] and identifies errors and their magnitude without tuning it to experimental work. The focus is put on validating design values such as tensions and to some extent, motions, as these determine the applicability of a certain mooring layout.…”

Section: Introductionmentioning

confidence: 99%

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Validation of a Tool for the Initial Dynamic Design of Mooring Systems for Large Floating Wave Energy Converters

Thomsen

Ferri

Kofoed

2017

JMSE

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Mooring of floating wave energy converters is an important topic in renewable research since it highly influences the overall cost of the wave energy converter and thereby the cost of energy. In addition, several wave energy converter failures have been observed due to insufficient mooring systems. When designing these systems, it is necessary to ensure the applicability of the design tool and to establish an understanding of the error between model and prototype. The present paper presents the outcome of an experimental test campaign and construction of a numerical model using the open-source boundary element method code NEMOH and the commercial time-domain mooring analysis tool OrcaFlex. The work used the wind/wave energy converter Floating Power Plant as a case study, which is defined as a large floating structure with a passive mooring system. The investigated mooring consists of a three-legged turret system with synthetic lines, and it was tested for both operational and extreme events. In order to understand the difference between the model and experimental results, no tuning of the model was done, besides adding drag elements with values found from a simplified methodology. This resembles initial design cases where no experimental data are available. Generally good agreement was found for the tensions in the lines when the drag element was applied, with some overestimation of the motions. The main cause of difference was found to be underestimation of linear damping. A model was tested with additional linear damping, and it illustrated that a final analysis needs to use experimental data to achieve the best results. However, the analyses showed that the investigated model can be used without tuning in initial investigations of mooring systems, and it is expected that this approach can be applied to other similar systems.

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Section: Design and Modeling Of Floating Structures With A Mooring Symentioning

confidence: 99%

Section: Optimized Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Validation of a Tool for the Initial Dynamic Design of Mooring Systems for Large Floating Wave Energy Converters

Thomsen

Ferri

Kofoed

2017

JMSE

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“…Additionally, which simulation procedure should then be used to carry out this initial fatigue design? Several references in the literature present investigations where, among others, power capture, motion behaviour of WECs, and mechanical characteristics of moorings are studied using the decoupled simulation procedure; see for instance Fitzgerald and Bergdahl (2008), Harnois et al (2015), Liu and Bergdahl (1997), Vicente (2009b), Vicente et al (2011a), and Vicente et al (2011b). There are also several investigations on the same topics where the coupled simulation procedure is used, see for instance Bhinder et al (2015), Cerveira et al (2013), and Palm et al (2013).…”

mentioning

confidence: 99%

A comparison of coupled and de-coupled simulation procedures for the fatigue analysis of wave energy converter mooring lines

et al. 2016

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Newcastle University ePrints -eprint.ncl.ac.uk Yang S, Ringsberg JW, Johnson E, Hu ZQ. A comparison of coupled and decoupled simulation procedures for the fatigue analysis of wave energy converter mooring lines. Ocean Engineering 2016, 117, 332-345. AbstractMooring systems for floating wave energy converters (WECs) must be designed to survive the cyclical loads and motions to which they are subjected as a result of the wave load-WEC interaction and the motions of the WEC in the random elevation of the sea surface. The current study compares simulation procedures for the fatigue analysis of WEC moorings. The objective is to suggest a simulation procedure suitable for an extensive study of the behaviour of WEC systems and thus for the fatigue analysis of mooring lines. A cylindrical, floating WEC with four spread mooring lines is chosen as case study. The dynamics of the WEC system are simulated and analysed using both coupled and de-coupled models in the timedomain. Four types of simulation procedures are compared using commercial software, DNV DeepC, and an in-house solver, MooDy. A systematic fatigue response analysis based on variations of the numerical and physical parameters is conducted. The results are compared with respect to the fatigue damage calculated using the stress-based approach and the rainflow counting method. The simulation procedure using a coupled model is suggested as the preferred numerical method for capturing the interaction between the components of WEC system, which is proven to be crucial for the fatigue damage evaluation of mooring lines.

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Numerical Modelling

Vyzikas

Greaves

2018

Wave and Tidal Energy

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Numerical model validation for mooring systems: Method and application for wave energy converters

Cited by 51 publications

References 8 publications

Validation of a Tool for the Initial Dynamic Design of Mooring Systems for Large Floating Wave Energy Converters

Validation of a Tool for the Initial Dynamic Design of Mooring Systems for Large Floating Wave Energy Converters

A comparison of coupled and de-coupled simulation procedures for the fatigue analysis of wave energy converter mooring lines

Numerical Modelling

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