PONE-D-22-25640Numerical assessment of wake-based estimation of instantaneous lift in flapping flightPLOS ONE

Dear Dr. Colognesi,

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Academic Editor

PLOS ONE

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“Victor Colognesi is supported by a FRIA grant from the Fonds de la Recherche Scientifique de Belgique (F.R.S.- 404 FNRS). 405 This work is part of a project supported by the ARC program of the Federation Wallonie-Bruxelles (grant 406 number 17/22-080, RevealFlight). 14 407 Computational resources have been provided by the Consortium des Equipements de Calcul Intensif (CECI), 408 funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under Grant No. 2.5020.11 and by 409 the Walloon Region. 410 The present research also benefited from computational resources made available on the Tier-1 supercomputer 411 of the Federation Wallonie-Bruxelles, infrastructure funded by the Walloon Region under the grant agreement 412 1117545.”

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“Victor Colognesi is supported by a FRIA grant (Grant number FC 21291) from the Fonds de la Recherche Scientifique de Belgique (F.R.S.- FNRS, https://www.frs-fnrs.be/en/).

This work is part of a project supported by the ARC program (grant number 17/22-080, RevealFlight) of the Federation Wallonie-Bruxelles (https://www.federation-wallonie-bruxelles.be).

Computational resources have been provided by the Consortium des Equipements de Calcul Intensif (CECI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under Grant No. 2.5020.11 and by the Walloon Region.

The present research also benefited from computational resources made available on the Tier-1 supercomputer of the Federation Wallonie-Bruxelles, infrastructure funded by the Walloon Region under the grant agreement 1117545.

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Reviewers' comments:

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Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This work introduces a lift estimation technique for large Reynolds number flapping flight. The paper is well written, and the arguments are convincing. However, there are some major revisions needs to be done to improve the quality of this work:

• This study derives and then validates an instantaneous lift equation using numerical simulation data of a flapping flight model. However, no validation data for the numerical solver had been provided. At the least, velocity profiles and vorticity profiles at the Trefftz planes (using the numerical solver) need to be compared with the experimental data. Although the authors provided a reference for the solver details, this comparison needs to be shown in the main manuscript. Without these comparisons with the experimental data, the validity of the solver remains questionable.

• The authors mentioned that AS6092 (bird-like) airfoil was used for the simulations. However, the simulated bird was Geronticus Eremita. This fact largely undermines the validity of this study as a slight difference in camber or curvature (with the actual bird airfoil) would produce significant difference in numerical simulation compared to the experimental data.

• Again, birds’ airfoil can vary significantly along the span in terms of camber and chord length. The authors didn’t mention anything about the differences between the model and the actual bird (Geronticus Eremita). A figure showing the wing model as well as the actual bird wing is required to be added in the manuscript.

• Also, this study lacks content. I would expect the authors to include some contents that show variations of lift as a function of the AOA. Since this is a numerical experiment, this can be done after validating the solver data with the level flight of the bird (experimental data).

• It is not clear to me how mathematical operations for the surface integral of the velocity were done to turn it into a surface integral of vorticity*distance (equation 12 in appendix). Can you please show the step by step processes?

• The figures (4a-5d, 7) need line legend.

• I would recommend authors to add more contents/pictures in Figure 3 (evolution of wake vortices). As this is a numerical simulation, the authors should be able to provide a much more detailed picture of evolution of vorticity at the wake.

• To use the lift equation (equation 5), is there any requirement to use threshold on the vorticity maps? Did the authors use any threshold on Figure 3?

Reviewer #2: Dear authors,

I have attached my comments on your manuscript (PONE-D-22-25640) in two .pdf files.

The first .pdf file contain specific comments, and the second .pdf file consists of some minor grammar mistakes and typos to address.

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Reviewer #1: Yes: Asif Shahriar Nafi

Reviewer #2: Yes: Hadar Ben-Gida

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Attachments

Attachment

Submitted filename: Review.docx

Attachment

Submitted filename: Paper_Review.pdf

Attachment

Submitted filename: PONE-D-22-25640_reviewer.pdf

PONE-D-22-25640R1Numerical assessment of wake-based estimation of instantaneous lift in flapping flight of large birdsPLOS ONE

Dear Dr. Colognesi,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Apr 28 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Roi Gurka

Academic Editor

PLOS ONE

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Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: (No Response)

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Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: Yes: Hadar Ben-Gida

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[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

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Attachments

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Submitted filename: Paper_Review_R1.pdf

Numerical assessment of wake-based estimation of instantaneous lift in flapping flight of large birds

PONE-D-22-25640R2

Dear Dr. Colognesi,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

Roi Gurka

Academic Editor

PLOS ONE

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