A model for quick load analysis for monopile-type offshore wind turbine substructures

Schløer, Signe; Garcia Castillo, Laura; Fejerskov, Morten; Stroescu, Emanuel; Bredmose, Henrik

doi:https://doi.org/10.5194/wes-3-57-2018

Articles | Volume 3, issue 1

https://doi.org/10.5194/wes-3-57-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue:

The Science of Making Torque from Wind (TORQUE) 2016

https://doi.org/10.5194/wes-3-57-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 3, issue 1

Research article

|

05 Mar 2018

Research article |

| 05 Mar 2018

A model for quick load analysis for monopile-type offshore wind turbine substructures

Signe Schløer, Laura Garcia Castillo, Morten Fejerskov, Emanuel Stroescu, and Henrik Bredmose

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Final revised paper (published on 05 Mar 2018)
Preprint (discussion started on 06 Mar 2017)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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SC1: 'Nice work, congratulations!', Frank Lemmer, 10 Mar 2017
- AC3: 'Thanks', Signe Schløer, 26 Jun 2017
RC1: 'Review 2017-11', Anonymous Referee #1, 23 Mar 2017
- AC2: 'Answers to review', Signe Schløer, 26 Jun 2017
RC2: 'Review comments', Michael Muskulus, 24 Apr 2017
- AC1: 'Answers to review', Signe Schløer, 26 Jun 2017

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (05 Jul 2017) by Carlo L. Bottasso

AR by Signe Schløer on behalf of the Authors (11 Sep 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (16 Sep 2017) by Carlo L. Bottasso

RR by Michael Muskulus (12 Oct 2017)

Suggestions for revision or reasons for rejection

This is a review of a revised manuscript which I previously reviewed. I will keep my comments short therefore.

The manuscript is generally well written and the topic is interesting. The authors have satisfactorily adressed my previous comments and I would like to recommend this manuscript for publication. Two small issues should still be corrected, however:

1. The frequency domain method is used with phases included here, which is somewhat unusual - but of course nothing wrong with this. It just means that the method is equivalent to time domain calculations. Computationally, there is not much to be gained here, since for this decoupled analysis the use of an impulse-response-function (as by Schafhirt et al.) can be evaluated with the FFT as well. The observation (p2, l1) that the use of impulse-response-functions needs the manufacturer to share confidential information is not accurate. The only information that is needed is a number of impulse-response-functions, which is similar to the situation in QuLA, where also some information about the support structure, e.g., a mode shape is needed. This should be corrected in the text. I would also suggest to mention already in the abstract that the frequency domain "with phases" is used, for the benefit of readers.

2. p6, l14: I assume that the reason why the wave kinematics are transformed to the time domain are the nonlinearities in the hydrodynamic force calculation? (Otherwise one could solve the equation of motion directly in the frequency domain) This could be mentioned here explicitly.

Small textual corrections:

p11, l8: "is calculated alternatively in Flex5"?
p13, l13: "see Fig. 7, lower plot, "?
p16, l2: "rated rotor speed"?
p18, l12: "decay tests results in the best agreement"?
p21, l10: "to the moment"?
p21, l17f: "are part of the exceedance"?
p22, l9: "which the spectra are based on."?

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RR by Anonymous Referee #1 (13 Oct 2017)

ED: Publish subject to minor revisions (review by editor) (16 Oct 2017) by Carlo L. Bottasso

AR by Signe Schløer on behalf of the Authors (01 Nov 2017) Author's response Manuscript

ED: Publish as is (06 Nov 2017) by Carlo L. Bottasso

ED: Publish as is (12 Nov 2017) by Gerard J.W. van Bussel (Chief editor)

AR by Signe Schløer on behalf of the Authors (19 Nov 2017)

Short summary

A model for quick load analysis is presented. This is a fast model for the calculation of dynamic loads of an offshore wind turbine tower and foundation. The model is compared to the state-of-the-art aeroelastic code. In general, there is good similarity between the two models. This indicates that in the early stage of the design phase a simple dynamic model can be used to make a preliminary design of the foundation and wind turbine tower.