Numerical Simulation of the Trajectory of UAVs Electrostatic Droplets Based on VOF-UDF Electro-Hydraulic Coupling and High-Speed Camera Technology
, Jun Hu 1,2,3,*, Yufei Li 1,2,3, Shengxue Zhao 1,2,3, Qingda Li 1,2,3, Wei Zhang 1,2,3 and Mingming Zhao 4
Round 1
Reviewer 1 Report
I. General conclusions:
1. Congratulations for the paper! Interesting and actually topic!
2. Please, try to compare the title, aims in abstract and introduction, method, and results!
3. Please, pay attention to abbreviation (must be defined). Sometimes there are repetitions (example „UDF function” means „user-defined function function”).
4. Use SI units (example: for pressure Pa)
II. Particularly observations
1. Introduction
Generally, the analyze is clear, comprehensive and relevance to the field.
In this area the presented paper’s aim can be more synchronized with title and other chapters. A short comment to the row 83, please, if possible, add a reference to presented idea.
2. Material and methods
Please keep in mind the results are reproducible based on the details given in the methodology section. The experiment can be presented more clear, re-structured on technical logical flow.
Please use SI units.
Figure 5 can be clearer, and the axis can have complete description (measure units, name).
Usually at methodology are not introduced results and discussion, I suggest reorganizing it.
Row 165, “the droplet density is set to 998.2 g·cm−3 ”, I think is a big mistake. (What material?)
Subchapter 2.2.5 can be systematized and enriched.
3. Results and discussions
Why firstly experiment and after simulation? Must be justified also in methodology or reorganized. I think an algorithm of experiment presented in methodology can improve the quality of the paper.
Results must be correlated with title, objectives, and methodology.
At discussions, did you see the results presented in Appl. Sci. 2021, 11, 4071, https://doi.org/10.3390/app11094071 ?
4. Conclusions
Conclusions are consistent with the evidence and arguments presented.
Author Response
Response to Reviewer 1 Comments
General conclusions:
1.Congratulations for the paper! Interesting and actually topic!
2.Please, try to compare the title, aims in abstract and introduction, method, and results!
3.Please, pay attention to abbreviation (must be defined). Sometimes there are repetitions (example „UDF function” means „user-defined function function”).
4.Use SI units (example: for pressure Pa)
Response :
- Thank you for your recognition of our work.
- The full name is given where it first appeared (lines 23-24).
- Usually the spray pressure is MPa or Bar. Other than that, the other units were converted to SI
Particularly observations:
Main issue 1: Introduction
Generally, the analyze is clear, comprehensive and relevance to the field. In this area the presented paper’s aim can be more synchronized with title and other chapters. A short comment to the row 83, please, if possible, add a reference to presented idea.
Response 1:
“Especially in [23], the spray characteristics including droplets size and velocity under different electrostatic voltages are investigated systemically and its result conclude that the electrostatic force could assuredly affect the movement characteristics for small size droplets, but the actual movement track and change pattern of droplet are not shown. In other words, non-visual studies reach conclusions that lack verifiable evidence.”(lines 85-90)
Main issue 2: Material and methods
Please keep in mind the results are reproducible based on the details given in the methodology section. The experiment can be presented more clear, re-structured on technical logical flow.
Please use SI units.
Figure 5 can be clearer, and the axis can have complete description (measure units, name).
Usually at methodology are not introduced results and discussion, I suggest reorganizing it.
Row 165, “the droplet density is set to 998.2 g·cm−3 ”, I think is a big mistake. (What material?)
Subchapter 2.2.5 can be systematized and enriched.
Response 2:
Amendments relating to international units as in general conclusion
Figure 5 shows the residual results automatically output by Fluent simulation software. We have further enlarged Figure 5, but the horizontal and vertical coordinates are the step size and residual results of the software's fixed output. If the reviewer still thinks this part needs to be modified, please contact the author.
The droplet density is set to 998.2 (kg·cm−3). (Line188)
Main issue 3: Results and discussions
Why firstly experiment and after simulation? Must be justified also in methodology or reorganized. I think an algorithm of experiment presented in methodology can improve the quality of the paper.
Results must be correlated with title, objectives, and methodology.
At discussions, did you see the results presented in Appl. Sci. 2021, 11, 4071, https://doi.org/10.3390/app11094071 ?
Response 3:
The whole article is written in the order of firstly simulation and after experiment. In the section of materials and methods, the test instrument is shown first and then the test simulation method is introduced. Because this order allows the simulation method to directly elicit the simulation results But the results and discussion section, simulation results are written first.
We have seen this article before, some electrostatic spray parameters were published by team members such as Lian [34].
The experimental algorithm has been presented in the attachment [Line192].
We would like to thank the referee again for taking the time to review our manuscript!
Reviewer 2 Report
References are few. Could have included more literature survey about the similar work. Could have included the description of TEMA software.
Author Response
We would like to thank the referee again for taking the time to review our manuscript!
Thank you for your recognition of our work!
Some references have been added. [21] and [26]
Reviewer 3 Report
1. It should be explained to the abbreviation of “UDF-VOF” in the abstract part.
2. “Unmanned Aerial Vehicles” should be installed of “UAVs” in key words.
3. Line 131: “The maximum calculation area of the simulation test is 5m*3m*4m.” Is not correct. It should be volume, not area.
4. Sourse links should be represented for (1), (2) and (3) equaitions.
5. Line 141: Where φ is electrostatic potential (v). But there is not φ in the formula (1).
6. It should be explained what mean in formula (2) and q, E in formula (3).
7. Figure 5 is not seen clear, the quality is low.
8. The values of droplet movement time in figures 10-14 and droplet movement speed in figures 15-16 are not seen well. They should be expanded to the size which we should see them.
Author Response
Response to Reviewer 3 Comments
Main issue 1: It should be explained to the abbreviation of “UDF-VOF” in the abstract part.
Response 1: It has been reflected in the article.（line 23-24）
Main issue 2: “Unmanned Aerial Vehicles” should be installed of “UAVs” in key words.
Response 2: It has been reflected in the article.（line 35）
Main issue 3: Line 131: “The maximum calculation area of the simulation test is 5m*3m*4m.” Is not correct. It should be volume, not area.
Response 3: It has been reflected in the article.（line 146）
Main issue 4: Sourse links should be represented for (1), (2) and (3) equaitions.
Response 4: It has been reflected in the article [27]
Main issue 5: Line 141: Where φ is electrostatic potential (v). But there is not φ in the formula (1).
Response 5: φ is in the formula (1).
If the reviewer thinks there are other parts that need to be added, please contact us
Main issue 6: It should be explained what mean in formula (2) and q, E in formula (3).
Response 6: It has been reflected in the article.（line 160-161）.
Main issue 7: Figure 5 is not seen clear, the quality is low.
Response 7: We have further enlarged Figure 5.
Main issue 8: The values of droplet movement time in figures 10-14 and droplet movement speed in figures 15-16 are not seen well. They should be expanded to the size which we should see them.
Response 8: It has been reflected in the article.（figures 10-14 and figures 15-16 ）.
We would like to thank the referee again for taking the time to review our manuscript!
Reviewer 4 Report
Dear Authors congratulations on the work done. I revised your paper which I found interesting and with a good novelty level. Anyway, I have to highlight that this study is very preliminary and your statements require deep investigations because you have tested the system in laboratory conditions, I am wondering what happens in the real environment? Some statements are good and relevant and can be used to better address field experimentation.
Comments for author File: 
Comments.pdf
Author Response
Response to Reviewer 4 Comments
Main issue 1: line 23 insert in full the acronym UDF-VOF
Response 1: It has been reflected in the article.（line 23-24）.
Main issue 2: line 99: particle size range 150-350 μm . This wide range represents a great limitation in achieving spray uniformity. Please insert the ISO 25358:2018 for spray classification
Response 2: It has been reflected in the article.（line 107-110）.
Main issue 3: Line 100 insert also the BBCH scale
Response 3: It has been reflected in the article.（line 111）.
Main issue 4: Line 104 remove the word “measuring”
Response 4: Have been removed
Main issue 5: Line 105 correct the verb
Response 5: It has been reflected in the article.（line 116）.
Main issue 6: Line 107 this is not clear, did you set a range from 6 to 20 kV?
Response 6: That means: The voltage can be adjusted in the range of 6-20kv
Main issue 7: Line 108 correct use SI for symbology “kv” and how do you measure the liquid pressure
Response 7: All kv in the text has been replaced with kV. The liquid pressure is monitored by the Chinese Suxun SUX 90A-0-10 MPa diffusion silicon pressure sensor.(Line 118-120)
Main issue 8: Lines 102 and 105 centre the images
Response 8: The journal format is images on the left side of the page. (If we do not understand your meaning, please contact us further. Thank you!).
Main issue 9: Line 117 Table caption, change with main features
Response 9: .It has been reflected in the article.（line 129）.
Main issue 10: Line 118 insert a space below the table 1
Response 10: .It has been reflected in the article.（line 130）.
Main issue 11: Line 118 please provide a more clear description
Response 11: .It has been reflected in the article.（line 131-132）.
Main issue 12: Line 119 How did you adjust the angles?
Response 12: The target is placed directly below the electrostatic nozzle, and the shooting position of the camera is at the same level as the target. This horizontal position is the best angle for the pictures.
Main issue 13: Line 131 How did you set this area?
Response 13: When the Angle of the shot is determined, the TEMA software automatically divides the grid area according to the particles it tracks
Main issue 14: Line 132 How did you generate lateral wind? Which kind of fun? Where didyou put it?
Response 14: In the computational domains for cross wind stage of simulation, the airflows were created along the X direction. The two ends in the X direction were set as the velocity-inlet and pressure-outlet. The other boundaries for the sides, top and bottom were set as a no-slip wall. (Line:171-174)
Main issue 15: Line 137 and 138 Did you consider the air temperature and air umidity? Which were the setting criteria?
Response 15: The general indoor standards of the time were adopted. The simulated temperature was set at 23° and the humidity at 40% (Line:146-147)
Main issue 16: Line 163 Please write in full DPM
Response 16: It has been reflected in the article.（line 185）.
Main issue 17: Line 176 How did you set the angle at 75°?
Response 17: It has been modified. The spray conical angle of 75° was obtained by simulation experiment. （line 199-203）.
Main issue 18: Line 176 How did you set the angle at 75°?
Response 18: It has been modified. The spray conical angle of 75° was obtained by simulation experiment. （line 199-203）.
Main issue 19: Line 178 you stated “the model has a good agreement” please provide further description because this paragraph is not clear
Response 19: Combined with the content modified in Response 18: The spray conical angle obtained by simulation is 75°, while the actual spray angle is 77°, so the model has a good agreement.
Main issue 20: Line 286 Please provide the diameter of the 12 droplets, this is a relevant pa
Response 20: .It has been reflected in the article.（line 365）.
We would like to thank the referee again for taking the time to review our manuscript!
