Influence of Wind Barriers with Different Curvatures on Crosswind Aerodynamic Characteristics of a Train-Bridge System
Round 1
Reviewer 1 Report
This paper would be of interest to civil engineers as well as wider academic community interested in aerodynamics. It is within the scope of the journal. The title is not great and the abstract needs work as it does not summarize the contents well. The structure of paper is good. A good background is given acknowledging appropriate previous work. The problem is well specified.
Some changes are recommended to improve clarity and the paper requires extensive grammatical corrections throughout. All findings are reported in 2D so it is assumed the CFD work is all in 2D, if not this should be clearly stated and depth dimension added to figure 2.
Change title to: Influence of wind barriers with different curvatures crosswind aerodynamic characteristics in two dimensions of a train-bridge system
Rework abstract to add more detail and include more key findings.
Should state train is at rest and results could differ if train was in motion, also crosswind is at zero yaw throughout so 2D assumption is used. Should also acknowledge only curvature is investigated here but slanted barriers and variations in height could also be studied in future work.
Line 82 add that ‘are obtained by 2d’ numerical simulations.
Line 85, define what is ‘A train’ ?
Lin91/92 b and c wrong in caption
Lin124 add in 2d to caption
Remove figure3b as all cfd work is in 2d
Line 148 The use of CD is confusing, perhaps a better definition would be sideforce (Cs) and also for Cm, perhaps roll coefficent would add clarity (Cr)
Line 171 blockage
Would be better to add 100% or no fence to table 1 and also figure 7
Maybe figures 8 and 10 could be combined to better aid comparisons
Maybe figures 6 and 12 could also be combined to better aid comparisons
Line 345 state wind angle from vertical as could be confused for yaw
Figure 13 changed so drag, lift, Cm is side by side, train on left, bridge on right to aid clarity
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors investigated the effects of curved wind barriers with different curvatures and train-bridge combinations on the aerodynamic characteristics of the train-bridge system using both numerical and experimental works. Their results showed that the curved wind barrier can reduce wind speed below a certain height. They concluded that the small curvature in a wind barrier can provide better protection for a train while increasing the aerodynamic force of the bridge.
The manuscript has grammatical issues which need to be corrected. Additionally, there are ambiguities regarding the experimental work, numerical simulation, and validation in the manuscripts that are needed to be addressed in order to be published. Further comments are demonstrated as below,
- The first sentence of the abstract has ambiguity. Please explain more clearly.
- Line 21: when the curvature 0.35 is specified, it would be needed to mention all other values and explain why this specific value would give better protection on the train-bridge system. (Rather the 0.2)
- Line 69: please mention the references on the curved wind barrier and explain why your work is different than others. Please highlight the purpose and importance of your work.
- Which parts of the project are investigated using theoretical analysis?? (As mentioned in line 72)
- Line 73 is not clear!
- There are several grammatical issues in the manuscript that are needed to modify.
- Line 74: Elaborate on the DDES method and why it was chosen amongst the turbulence models?
- What do you mean by train-bridge combination?
- Line 81: Specify the “pressure cloud diagrams, aerodynamic coefficients” and explain them briefly.
- Line 85: this is not clear!
- The equations for the numerical simulation are missing! Equations, discretizations, and the methods in each equation need to be specified.
- Figure 3a does not clearly demonstrate the train and bridge geometry!
- Line 115: Please explain the sentence “the turbulent wake needs to diverge completely”
- Line 143: I guess this section is not Data processing and only define the parameter for the next sections
- Figure 4 only shows a schematic image of experimental work and Figure 5 is not quite clear. I suggest adding images of the real experimental works including the wind tunnel and the train-bridge system
- Line 163: Please specify the velocities you chose for the experiment (besides the velocity range)
- Line 169: How did you have the porosity in the wind barriers? What was the process?
- How did you define the moment coefficient in the experimental work?
- There are no Figures regarding the results of numerical simulation in the validation section.
- Please specify at what velocities, the wind barrier is not providing any protection (for instance section 4.1)
- Line 206: Why the C3 wind barrier is better than C2? Why the trend is not consistent?
- It would be better to present the velocity vector or streamline in the results (Figure 6)
- Line 225: what are y and Hb
- Please address X in Figure 7 and show the parameters in the schematic figure
- Explain the significant changes in Figure 7 (a) to (f) when the X changes
- Why there are no consistent trends between C1, 2, 3, and 4 in each figure of figure 7 (for instance abrupt changes in C2 and 3 in Figure 7 (a))
- Why it was concluded that C3 would be the best option, even C2 has smaller curvature? Is there any theoretical analysis behind this?
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
It is a nice piece of work that will be of good interest to fluiddynamics and civil engineering community.
Authors investigated the aerodynamic features of train-bridge system based on CFD simulation in detail.
I recommend this paper to be accepted after the following minor concerns are addressed.
1) page 3: “… shear stress transport (SST) …” is more commonly used rather than “shear stress transfer …” in line 102.
2) There are various parameters/symbols in the main text. It would be better to add nomenclature section to clarify them at a glance.
3) It seems that aerodynamic coefficients in CFD results are evaluated based on time-averaged values. On the other hand, the maximum load is one of the important properties to design train & bridge structures. Did maximum aerodynamic coefficients show similar trend as time-average ones?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have improved the paper and made appropriate changes to most of the comments. They have provided good rationale for not making some changes.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The authors provide significant changes to the manuscript. I am content with most of the modifications. There is only one comment that I mentioned previously (comment 19) and it would be better if the authors include the geometry and some qualitative results (not quantitative results that were already presented in table 1) from the numerical simulation in the validation section. The authors can include them in the appendix section as well.
Author Response
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Author Response File: Author Response.pdf
