Analysis of Influence of Different Parameters on Numerical Simulation of NACA0012 Incompressible External Flow Field under High Reynolds Numbers

Round 1

Reviewer 1 Report

Manuscript presents interesting simulation results. From technical point of view this manuscript is acceptable for publication, although English proofread is highly recommended. Additionally, rather minor remarks should be included before publishing the manuscript.

1. Is it necessary to provide so many significant numbers in Eq. (1)? The same question goes to tables 5-10 and figures 6-12, and to appropriated sections.
2. Improve quality of figures: 1, 2, 4a, 6-11, 13-15, 17-18
3. Section 3.2 and Table 4. Unit of viscosity should be kg/(m×s) (or kg/m/s) and Pa×s
4. Tables 5-10. Add space between numbers and “points”.
5. Avoid double titles of figures, for example fig. 12-19.

Author Response

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Reviewer 2 Report

The numerical results are described in detailes. The natural experiments almost are not described. So it is difficult to check the correspondence of different numerical results with real data.

Author Response

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Reviewer 3 Report

First of all I would like to underline the considerable amount of data produced, which demonstrates attention and methodical commitment

There are, however, in my view, some issues and problems that need to be resolved.

To begin with, the simulations were carried out using - as seems to emerge from the references - Ansys Fluent. However, the product is never specifically mentioned, while it should be. And here comes the most delicate point: summing up the work it can be described as a parametric analysis of the ability of the code used to describe the fluid dynamic field around the profile as a function of some parameters. A kind of benchmark of the code used; benchmark that could completely change by changing code (for example CFX, OpenFoam) with the same solvers or turbulence models, and meshes, used. This work therefore has the characteristics of a technical report, and summarizes a series of fairly common operations in the validation of simulations used to study fluid dynamics problems. The question I ask the authors is therefore: what does it add, what is the contribution, the novelty that this work brings to the scientific community?

This point does not emerge clearly neither from the introduction nor from the conclusions, also thanks to a presentation of the results to be reviewed in terms of formatting and organization. I refer to the results proposed from page 14 onwards, a dispersive and very difficult to follow list of values, also due to the size of the characters used in the plots and captions, which absolutely requires a revision in order to facilitate the reader in understanding the data.

finally some questions:
why choose a pressure of 105 kPa?
Why is the incompressible flow velocity reported in terms of Mach having a BC velocity -inlet?
Why is the wall isothermal and not adiabatic?
Why is the dynamic viscosity 1.047e-5 and not 1.8e-5 Pa s? If this last value were to be wrong it would affect all simulations

Author Response

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Reviewer 4 Report

Reviewer #: The paper is a theoretical one, however, it would be interesting to compare or calibrate it on real data in order to obtain better quantitative results. I understand this is beyond the scope of the paper and quite difficult to find available NACA0012 13Airfoil real data. This study investigated in detail the effect of shape of the trailing edge, the far-field distance, and the turbulence model on the hydrodynamic characteristics and flow field developing around the NACA0012 based on numerical simulation.  A numerical model was implemented based on the CFD technique using SST k-omega turbulence model.  The findings enable more accurate simulation models, the prediction of the hydrodynamic performance of NACA0012 13Airfoil. As general comments, the originality of this study is not clear for me. The authors introduce the previous studies related to the analysis of the flow field around the NACA airfoil in the introduction. The authors must emphasize the difference of their study from the previous studies. Also, the results were not analyzed but listed. Unfortunately, this manuscript does not meet the standards for publication in applied sciences for the reasons listed below and should be thoroughly revised before possible publication.

1. I find the analysis hard to follow and confusing. In a general way, I think the authors have to improve the clarity and quality of the text, which is sometimes difficult to follow and to understand. It also contains incorrect statements and equations. I believe that significantly deeper physical insight would be required to publish these research results.
2. A complete review of grammar and style must be done in order to improve the quality of the publication.
3. The authors must rewrite the abstract in order to better present their finding because it is difficult to follow and to understand what exactly they have found.
4. Line 27-28: the authors have to prove by comparing the results obtained using this turbulent model and existing experiment data that the using of the parameter configurations of sharp trailing edge, far-field distance and SA/SST/SST/SST/SST/SA turbulence model could obtain the best simulation effect.
5. In the introduction the author not have to use the word as by the author(line 39) or Refs[9,10] (line 61) but they can used the word as in line 39 Lu and Guangming [3].
6. Was the simulation done in 2D or 3D? the authors have to mention it and explain the reason
7. Line 200 The authors would have to prove that the k-omega-SST model is as accurate as any other two equation model for the stated applications. The sentence should be corrected to be more specific.
8. The reviewer doubt that the stated discretisation scheme is applied to all terms of the equations. The authors should clarify this and specify the chosen
   schemes in more detail.
9. Table 2 for the grid independency analysis the authors have to choose a model with available experiment data aven if it is published data done previously to better explain the mesh reliability
10. Table 3 must be deleted because it is not necessary
11. Tables 5 and 6 have to be combine and the authors not have to show the results of all the attack angles maybe choose only three. Same for the tables 7 and 8, and tables 9 and 10.
12. The results are too bushy and impossible to follow. the authors must be more explicit in the analysis because the values can be read directly on the graphs
13. The quality of the figures should be improve
14. I think that the authors must separate the results from the discussion in order to make a good interpretation of the results obtained and to compare them with previous studies.
15. Conclusions read more like Abstract while they should be more about the implications of findings.
    
    

Comments for author File: Comments.pdf

Author Response

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Round 2

Reviewer 2 Report

All corrections have been done. Now I have no comments.

Reviewer 3 Report

I have seen the significant improvements made and I believe I have no other observations to make, apart from an invitation to check the formatting standards of the figures again.
Regards

Reviewer 4 Report

Compared to the first version of the manuscript, the present revision shows much more improvements.