Effect of Inter-Vehicle Suspension on Variable Speed Curve Running of Train under Crosswinds
Round 1
Reviewer 1 Report
Comments and Suggestions for Authorsv The authors worked on “Effect of Inter-Vehicle Suspensions on Variable Speed Curve Running of Train under Crosswinds”. The effect of IVS on the variable speed curve running of the train under crosswinds is studied. The difference in the vehicle dynamic of considering the IVS and the fixed connection under traction and braking conditions is analyzed. Following are some comments and queries that must be addressed.
v The flow connectivity is missing in the abstract section. Add existing challenges, proper methodology, objectives, and conclusion in the abstract section. No statistical data is presented in the abstract section. Please add quantitative data in the abstracts section.
v In the abstract section, there is a word CRH2. What does this mean?
v The introduction section is not properly organized. There are several sentences that are technically and grammatically wrong.
v Research gaps should be delivered in a more clear way with directed necessity for the conducted research work (Introduction).
v The novelty of the manuscript is not explained properly. The novelty of the current research work must be clearly addressed and discussed, compare your research with earlier research works and highlight the novelty.
v The main objective of the paper must be written at the end of the introduction section. There is no objective written in the current manuscript. The authors are requested to read some research papers on how to write objectives at the end of the introduction section.
v The quality of the figure 5 is low. Please redraw a clean and neat figure.
v Figure 6 belongs to the authors if not then properly cite it.
v It seems that the authors have applied some previous equations on common bodies. The authors should focus on their own research. The main thing is the input of the manuscript and the output must be explained in a proper way. They should identify properly the research gap. Moreover, the authors emphasized previous research of the various authors rather than their own research.
v The authors are considering various DOFs, but in the paper, no DOF is applied practically rather the author references the previous research work.
v The authors have conducted multi-body simulations but nothing is mentioned about the boundary conditions.
v The quality of the various figures is not good. Please add high-quality figures.
v It is not mentioned properly which software is used for numerical simulation. Please add.
v The results and discussion part is very short. Please add some more results in this section
v In the conclusion part, no quantitative data is presented and no comparison has been done properly for evaluation. It is very hard to understand which case gives better results and how is the impact of the optimized method.
v Technical writing is required throughout the whole manuscript. Found so many grammatical mistakes throughout the manuscript. Thus, the entire manuscript ought to be thoroughly elaborated, perhaps once again, by a properly skilled in this field English language expert
v The number of references is very less. Add more references
Comments on the Quality of English LanguageExtensive editing of English language required
Author Response
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Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe present study aims to evaluate the effect of IVS on the variable speed curve running of trains under crosswinds. The topic is important and interesting to the readers and appropriate for the scope of the Applied Sciences journal. The authors have contributed to establishing a three-vehicle dynamics model considering the IVS by using a multi-rigid body dynamics method. The introduction provides sufficient background and references. The research design and the methods are well described. The results are clearly presented. Overall, the paper is worthy of publication. However, the manuscript needs effort to improve its quality and meet a journal standard. Below are some comments to help the authors to improve the paper's quality.
1. The introduction should focus more on a multi-rigid body dynamics method. I suggest the authors add references and rewrite the introduction by identifying the novelty/gap between this study and current research trends, including discussing previous methods on a multi-rigid body dynamics method. The paper must offer a distinct novelty to the reader to be considered for publication.
2. I suggest the authors add more validation for the simulation results.
3. The limitations of the methods and simulation results should be presented because only specific cases and variables are used for simulation. Is it valid only for the case of the CRH2 high-speed train running on the Lanzhou-Xinjiang high-speed railway in China? It is better to add analyses and discussion in more general cases if possible.
4. The Conclusion needs to be written more generally and technically.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear authors,
Your article about mechanical response of running train to wind is interesting and from mechanical point of view is ok. But there is a huge lack of knowledge about the wind, especially the effect of turbulence. Turbulence contains all length-scales smaller than the integral length scale, the ratio of smaller ones roughly follow the Kolmogorov scaling E ~ k^{-5/3}, where k is the wavenumber of perturbation. The energy content decreases rather fast, but the issue is the Galilean transformation into the moving reference frame - that will decrease the length-scales AND increase the energy content (by increasing velocity, Your figure 5). The problem can occur at wavelength corresponding to some important size of the train: e.g. wavelength = car length => yaw oscillations; wavelength= car height => roll oscillations; wavelength = 2× car length => oscillations between neighboring cars etc. In Your figure 9, there is a resonance oscillation visible. The question is, if the damping at resonant ω is larger than the forcing from turbulence at corresponding k (transformed into moving frame). By the way, the "gust", You are talking about, is a consequence of non-linear energy transport across scales.
Maybe I am wrong, and this turbulence issue is weak enough to not affect Your conclusions. But in any case, it should be discussed in Your article. To get information about spectrum of ABL, You can look into some of articles: doi.org/10.1007/s10546-013-9903-1, doi.org/10.1175/JAMC-D-21-0014.1, doi.org/10.1007/s00348-014-1737-1, doi.org/10.1051/epjconf/20146702084, doi.org/10.3390/atmos12040421 and for north China (but it is about some haze period, You are interested in windy periods) doi.org/10.1016/j.envpol.2020.114726
Smaller issues:
- in equation (5) the second derivative is in respect to inertial reference frame, while the first derivative and displacement X are in respect to the equilibrium position/velocity in respect to the components connected to the studied component.
- some photograph of the dampers in Figure 7 should be added. I cannot really imagine these dampers, because they are clearly different from that, which is used in my country (in my country it looks like this: https://cs.wikipedia.org/wiki/Sp%C5%99%C3%A1hlo#/media/Soubor:Eisenbahn_Schraubenkupplung_1.jpeg therefore, the dampers produce zero force in case of larger displacement - they are not in contact, the attraction force is caused by the central connection only, so it is very different from the system used in China and described in Your figure 7)
- Figure 4: add the sketch of named moments, e.g. which rotation do You mean by "yaw", "pitch" and "roll"
After incorporating the fluctuation properties of wind OR after adding some science-based argument, that this effect is weak enough to be neglected, then the article will be ready to be published. Unfortunately, at current stage, I have to recommend "rejection".
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsI am satisfied with the author's responses but the English still needs improvement. for example
"In reference to Ling. et al. [15], we can see the side view in Figure 6a and the top view in Figure 6b of the dynamic vehicle model"
I don't understand what does this mean. These types of mistakes are also present in some other places. Please go through each and every paragraph for correction.
Figure 4, make all font black instead of using different colors.
Figures 13, 15, and 16, all percentages should be in black instead of light blue, Please correct. same way figure 18
Comments on the Quality of English LanguageEnglish needs further improvement.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper quality has been improved in a revised version. The authors have accommodated the reviewer's comment. I think the paper can be accepted for publication.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear authors,
I think, that the discussion about effect of wind turbulence could go little bit deeper. But it can be.
Author Response
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