Investigation of Aeroelastic Energy Extraction from Cantilever Structures under Sustained Oscillations

Round 1

Reviewer 1 Report

 

 

 

The manuscript is well-written and organized, however, there are some issues, which are mentioned in the following, that need to be revised or included in the text. Also, there are some writing errors that need to revise.

 

1.   Page 2: "more energy dissipated from it" should be "more energy is dissipated from it"

2.   Page 2: "more energy pumped into the plate" should be "more energy is pumped into the plate"

3.   Page6: "and for its low drag and great" should be " and for their low drag and great"

4.   Page 12: "are given as imput in the" should be "are given as input in the"

5.   Page 12: "the primary governing equations imposed in" should be "the primary governing equations are imposed in"

6.   In the introduction section, it needs to mention a literature review about the various application of Piezoelectric applications for energy harvesting in other areas such as medical equipment, the construction industry, health monitoring of structures, etc. The following reference as well as other references related to other industries for this purpose can be used.

DOI: https://doi.org/10.3390/bios13010037

7.   The parameters in equations 1 to 13 need to define properly in the manuscript.

8.   The quality of Figure 2 and 3 need to be improved (if possible).

9.   Figure 16, 17, 19, 20, 22, and 23 is unnaturally enlarged, it is better to reduce their dimensions. Also please increase their quality.

10.  It is better to state the percentage of maximum difference in figures 16 and 17 in the text.

11.  In all equations, the parameters need to be defined in the text.

12.  It is suggested that in the conclusion part, in addition to the presented qualitative conclusion, an example of significant results from the analysis also be presented.

 

Overall comment:

• Based on the previously mentioned comments, the reviewer would like to suggest consideration of this manuscript for publication after the inclusion of the suggested comments in a revised version of the manuscript.

 

 

 

 

Author Response

Dear Reviewer,

The response to your comments on the manuscript is consolidated as per the format given by MDPI and attached herewith. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript is more like an engineering report than a novel scientific publication. It does not show any novel simulation or measurement techniques, or scientific findings, and the investigated cantilever structure is actually not complicated. Therefore, the current format is not qualified as a high-quality research achievement.

1. The title of the manuscript should be simple and clear, covering the main research content in the main text.
2. The introduction should be organized in a clearer and more systematic way. Please clarify the difficulties of the current research topic clearly and list out the importance and innovations of this investigation.
3. The structure of the paper shall be listed in the last paragraph of the introduction.
4. The Mathematical methodologies of the analytical approach, FEA, CFD and FSI have to be reorganized in a logical way.
5. The corresponding experiment results of modal analysis, stress analysis and CFD calculations need to be provided.    
6. All graphics should be clear and with high resolution.
7. Grid Convergence Test of the stress analysis shall be supplemented, because the stress value is very sensitive to the local grid.
8. Grid Convergence Test of the CFD analysis shall also be added.
9. The conclusion is very poor and has to be improved.
10. Provide the list of abbreviations.
11. The English needs to be significantly improved.
e.g.  Equation (1) is gives the useful connection for the wing design. The comprehensive historical relationships of various relevant aircraft weight data is cumulatively revealed in Figure 1.
 ...is gives...?
 The authors can learn from the following article.
"Effective Writing", https://www.nature.com/scitable/topicpage/effective-writing-13815989

Author Response

Dear Reviewer,

The response to the comments given by youy are consolidated in a single document as per the format given by MDPI. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

In this paper, advanced partly coupled computational simulations are carried out with CFD, structural, and vibrational effects to investigate the energy harvesting potential from the perturbations. Based on the outcomes of vibrational analysis, the raw transformable power production capacity of different lightweight materials that are employed with a cantilevered PVEH is estimated. The review opinions are as follows:

1)      The first two paragraphs of the introduction also contain a background introduction to PVEH, and some documents need to be cited for supporting explanations.

2)      The general description of the introduction is a bit too much, it should be shortened to the focus.

3)      Abbreviations should be given their full name when they first appear, eg FSI. Secondly, the table of abbreviations at the end of the article is best sorted in the order of ABC.

4)      In Chapter 2.1, there are four levels of headings, and there are too many headings, which is not common. Please consider reducing the number of headings in this section, or providing sufficient explanation.

5)      In Chapter 2.1, please try to simplify the formulas and avoid complex ones, such as (2) (7) (17) (18) (21) etc.

6)      The medium simulated in this paper is gas, why not consider compressible flow. Does incompressible flow correspond to objective reality?

7)      Figure 9 and Figure 10 are somewhat blurred, and the internal airfoil cannot be seen. It is recommended to add a detailed structure diagram, or to merge the previous schematic diagram of the airfoil.

8)      In Chapter 2.4, there are too many references [21-26], is it necessary?

9)      The parameters used in the formulas throughout the text are regular, which is not appropriate. In scientific literature, variables are in italics and constants in regular.

10)   Whether the article has the conditions to conduct experiments to testify the accuracy of the simulation, or other explanations to increase credibility.

11)   In the conclusion, some prospects for future work should be added, either in the academic field or in the application field.

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

Piezoelectric transducers are used to capture vibrational energy, yielding electrical energy. Higher energy extraction is possible from external perturbations on lightweight materials like aluminium alloy, GFRP, titanium alloy, CFRP, and KFRP when used with PVEHs. In the article, based on CFD simulation, structural and vibration modeling, an assessment of the energy harvesting potential was carried out. The most suitable combination of material and aeroelastic effect for obtaining significant energy has been proposed. The advantages of the work include a comparison of theoretical results with experiment, which showed the adequacy of the model.

However, there are a number of remarks.

1.      The purpose of the work should be stated in the introduction. The conclusion is well written, but only from it will we learn what the authors wanted to do.

2.      Literature Survey. It seems that the authors have collected relevant articles and their abstracts in disorder without critical analysis. There is no conclusion about what has already been done and what problems have NOT been solved. For example, page 4, last paragraph. “This work…” In what work? [18]? It seems that the authors simply take abstracts from the works. Even the AI could have made the review better.

3.      2.1. Proposed Designs, 1 paragraph. Figure 2 is different. By the way, point, please, the source of this information in the Figure 2?

4.      Equation 1 source? Source of the following equations? What works do these equations follow from? Not all symbols in the equations are deciphered (even taking into account the summary table at the end of the article).

5.      Results and Discussions. Here, finally, the purpose of the work is formulated. It would be nice to put it in the introduction. Although it can be repeated here too.

6.      On fig. 15 no notation a, b, c

The advantages of the work include a comparison of theoretical results with experiment, which showed the adequacy of the model.

Comments for author File: Comments.pdf

Author Response

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Round 2

Reviewer 1 Report

Thanks for the revised manuscript. Hope to see more your research papers in this field.

Author Response

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Reviewer 2 Report

 It seems the author tried to explain the possibility of extracting energy from Cantilever Structures such as airplane wings and wind turbine blades, etc. However, the research approach has a fundamental mistake of getting some conclusions from a very simplified airfoil cantilever and then promoting the conclusions to the large complex airplane wings and wind turbine blades, etc. A large number of measurements have to be carried out on the scaled models and prototypes of airplane wings and wind turbine runners to prove the truth of the assumption.

And it fact this kind of assumption is also against the common sense of the design philosophy of airplanes and wind turbines, for them, safety is more important than just extracting a little bit more energy but increasing the complexity of the airplanes and wind turbines with more auxiliary pieces of equipment on them. It is not acceptable to expect they can have large deformations to extract some energy but threaten the safety of airplanes and wind turbines.

Author Response

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Reviewer 3 Report

Thanks for the modifications.

Round 3

Reviewer 2 Report

Every year there are too much damage and cracks on airplane and wind turbines. For them, safety is in the first place.  No one can guarantee that the first 5 free vibration modes cannot be excited on the airplane wings and wind turbine blades.

Solar panels integrated into airplane wings and wind turbine blades can be a more economic and feasible way to harvest energy instead of using PVEH patches.  The solar-powered plane has been already developed.

To harvest energy with vibration, the author may refer to the investment:  bladeless wind turbine generates electricity by vibrating with air movements.