Aeroelastic loads on a 10&thinsp;MW turbine exposed  to extreme events selected from a year-long  large-eddy simulation over the North Sea

Schepers, Gerard; van Dorp, Pim; Verzijlbergh, Remco; Baas, Peter; Jonker, Harmen

doi:https://doi.org/10.5194/wes-6-983-2021

Articles | Volume 6, issue 4

https://doi.org/10.5194/wes-6-983-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Wind Energy Science Conference 2019

https://doi.org/10.5194/wes-6-983-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 6, issue 4

Research article

|

07 Jul 2021

Research article |

| 07 Jul 2021

Aeroelastic loads on a 10 MW turbine exposed to extreme events selected from a year-long large-eddy simulation over the North Sea

Gerard Schepers, Pim van Dorp, Remco Verzijlbergh, Peter Baas, and Harmen Jonker

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Final revised paper (published on 07 Jul 2021)
Preprint (discussion started on 13 Feb 2020)

Interactive discussion

Status: closed

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

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RC1: 'Review wes-2020-1', Anonymous Referee #1, 31 Mar 2020
RC2: 'Review', David Verelst, 08 May 2020
AC1: 'Reply to reviewers', Gerard Schepers, 30 Jun 2020

Peer-review completion

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

AR by Gerard Schepers on behalf of the Authors (28 Aug 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (16 Oct 2020) by Katherine Dykes

RR by Pietro Bortolotti (30 Nov 2020)

Suggestions for revision or reasons for rejection

I would like to thank the authors for their great effort to improve their work. I believe that they have successfully addressed most of the concerns that the second reviewer and I raised during the first round of review.
I’m happy to say that my recommendation is now to accept this work for publication, pending minor revisions.
To try improving the paper a little further, I list here a few new comments:
1) Line 61: “In this way it can be assessed whether these extreme events yield loads which exceed the design load spectrum. If true, this might lead to a recommendation on adaptation of the load spectrum with events found in the present study.“ And if not, as it turns out? Adjusting the DLCs? Reduce safety factors? One of my concerns from the first review was the weak conclusions of the work. This aspect has greatly improved in the revised paper (thank you), but in my opinion the key takeaways may still benefit a few more thoughts. Given the results that you show, what do you recommend for the standard? What should a designer do after reading your paper? You list a more accurate wind modeling and the coupling to higher fidelity solvers among the next steps. But what do we do for wind parks where turbines are not isolated, but experience waked inflows? How would you model these phenomena in your numerical framework?
2) Line 114: “ERA5 boundary conditions”. What are they exactly? Also, no conclusion talks about them. Should one bullet point discuss the differences between GRASP and ERA5 outputs?
3) Figure 2 and Figure 6 have the top of the legend cut (1000 instead of 10000). The whole paper would also look so much nicer if all figures were generated with the same style, Matlab or Python or Excel or Paraview or … It could be a very easy and so useful upgrade.
4) Line 181: “However even a turbulence class C (the lowest possible turbulence class in IEC) leads to turbulence intensities which are still far below the extreme “. Shouldn’t the word be “above”? The extreme values observed are below the values from turbulence class C (and A), not vice versa, no?
5) Line 279: were the original loads run in Phatas? I tried to access the AVATAR deliverables to check myself, but the website seems to be down (or not accessible to me?). If they were, I find the fact that you rerun the loads irrelevant to the reader. I understand it was a useful step for you to avoid inconsistencies, but the reader does not gain anything here. I would remove the sentence at line 281/282.
6) Line 289: “The yaw angle is prescribed to be 8 degrees in line with the IEC standards.” Isn’t this condition for misaligned load cases only? That should not be true for DLC 1.2. What am I missing?
7) Figure 9: typo in the label of the y axis “Exterme”.
8) Line 361: “The variation in flatwise moment from the low-level jet is very different.“ Azimuthal variation? Or variation compared to what?

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ED: Publish subject to minor revisions (review by editor) (06 Dec 2020) by Katherine Dykes

AR by Gerard Schepers on behalf of the Authors (04 Feb 2021) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (04 Apr 2021) by Katherine Dykes

AR by Gerard Schepers on behalf of the Authors (10 May 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (17 May 2021) by Katherine Dykes

ED: Publish as is (17 May 2021) by Joachim Peinke (Chief editor)

AR by Gerard Schepers on behalf of the Authors (02 Jun 2021) Author's response Manuscript

Short summary

In this article the aeroelastic loads on a 10 MW turbine in response to unconventional wind conditions selected from a year-long large-eddy simulation on a site at the North Sea are evaluated. Thereto an assessment is made of the practical importance of these wind conditions within an aeroelastic context based on high-fidelity wind modelling. Moreover the accuracy of BEM-based methods for modelling such wind conditions is assessed.