Numerical Investigation on Flow Characteristics in a Mildly Meandering Channel with a Series of Groynes
Round 1
Reviewer 1 Report (Previous Reviewer 1)
Paper has been improved considerably. But I still don't see it as a major contribution to the understanding of river meandring and groynes.
In conclusions some more attention could be given to what the profession has learned from this research.
Author Response
We appreciate you for your precious time in reviewing and providing valuable comments concerning our manuscript entitled “Numerical investigation on flow characteristics in a mildly meandering channel with a series of groynes”. These comments are improving our paper and have important guiding significance for our research. According to your suggestion, we have further revised the paper. The point-by-point responses are as follows:
Point 1: In conclusions some more attention could be given to what the profession has learned from this research.
Response 1：In the latest version of the manuscript, the conclusion part has been revised. The results of numerical simulation are supplemented and summarized. The supplementary content is in line 495-502.
Author Response File: 
Author Response.pdf
Reviewer 2 Report (Previous Reviewer 2)
I acknowledge the efforts done by the Authors to improve the original manuscript (sustainability-2137554). However, the current manuscript could be considered for publication on "Sustainability" only after "major revisions" (see my comments in the attached marked manuscript). More importantly, the Authors should present all the steps of the set-up of the numerical simulations.
Comments for author File: Comments.pdf
Author Response
We appreciate you for your precious time in reviewing and providing valuable comments concerning our manuscript entitled “Numerical investigation on flow characteristics in a mildly meandering channel with a series of groynes”. These comments are improving our paper and have important guiding significance for our research. According to your suggestion, we have further revised the paper. The point-by-point responses are as follows:
Point 1: The presentation of the numerical model is not complete. Boundary conditions, model parameterization and meshing are missing. More importantly, the Authors should present all the steps of the set-up of the numerical simulations.
Response 1：According to the recommended references:
Blocken, B.; Gualtieri, C. Ten iterative steps for model development and evaluation applied to computational fluid dynamics for environmental fluid mechanics.
Gualtieri, C. "Numerical Simulation of Flow Patterns and Mass Exchange Processes in Dead Zones."
We have added a detailed description of the modeling set-up. The location of the changes is detailed in the 164-196 lines of the latest version of the manuscript. The latest manuscript is attached.
Author Response File: Author Response.pdf
Reviewer 3 Report (Previous Reviewer 3)
The revised paper has addressed the points I made satisfactorily.
Author Response
We appreciate you for your precious time in reviewing and providing valuable comments concerning our manuscript entitled “Numerical investigation on flow characteristics in a mildly meandering channel with a series of groynes”. These comments are improving our paper and have important guiding significance for our research.
Reviewer 4 Report (Previous Reviewer 4)
The authors have adequately responded to all my comments. After this last review, the authors have made changes and the paper has been improved significantly. The paper can be published.
Author Response
We appreciate you for your precious time in reviewing and providing valuable comments concerning our manuscript entitled “Numerical investigation on flow characteristics in a mildly meandering channel with a series of groynes”. These comments are improving our paper and have important guiding significance for our research.
Reviewer 5 Report (Previous Reviewer 5)
my comments have been addressed in full. I acknowledge the efforts made.
Author Response
We appreciate you for your precious time in reviewing and providing valuable comments concerning our manuscript entitled “Numerical investigation on flow characteristics in a mildly meandering channel with a series of groynes”. These comments are improving our paper and have important guiding significance for our research.
Round 2
Reviewer 2 Report (Previous Reviewer 2)
The manuscript can be accepted for publication. but a final proof-reading is advisable.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The flow in river meanders has been researched by many authors. The flow is rather complicated and has a very strong three dimensional character. There are hundreds of publication on this matter. It is not clear what this paper intends to add to the existing literature. In section 2 the basic formulas for river flow are presented, but it is not explained in how far this model is an improvement of other, existing models. The explanation of the used model is rather poor.
The data are compared with an experiment, and it seems that the model reproduces the experiment rather well. But in none of the figures I see the three dimensional character of the flow.
The quality of the language is very poor. Even for a non-native English speaker it is remarkable that there are many mistakes in the English language. Notably the difference between singular and plural words goes wrong (e.g. line 34: …. groyne are still..). Many acronyms are not explained (e.g. what 9s a EPS enhanced groyne, line 54). In line 56 the “strength of the outbank cell” is mentioned. It is not made clear what this means. Also “cocolog groynes” are not explained. Only after an internet search with pictures I get an idea what is meant, but inn the paper is not explained.
Table 1 is rather confusing, especially because there column NG is blank.
In figure 2 is shown that the numerical model and the physical scale model give rather well agreement, but nothing is said about the settings of the model.
In section 2.3 a case with groynes is shown. But in section 3 I see only a description of the results, but no link to the physical processed.
In the list of refence the literature review by Yossef is dated 2022 (it was placed by , but this report is from 2002. Why refiring only to his literature review, and not to his model research (see his PhD thesis from 2005).
Reviewer 2 Report
The manuscript could be considered for publication on "Sustainability" after "major revisions" (see my comments in the attached marked manuscript).
Comments for author File: Comments.pdf
Reviewer 3 Report
A RANS (RNG) model is used to simulate flow in a gently meandering channel with different arrangements of groynes to investigate preferred arrangements for reducing erosion. Four groynes are used of different lengths and orientations. The model is validated against some experimental results and some mesh refinement tests have been undertaken (although not reported on in any detail). The results are useful and interesting. The overall structure of the paper is OK, but there are some presentational aspects that need to be addressed.
A The paper needs checking thoroughly for English. Below I give some corrections from the Abstract and Introduction by line number, but there are more throughout the paper.
8 groynes are
9 a three-
16, 34, 35 groynes
38 After groynes are introduced, the original ..
42 in a bend channel
47 increased with an increase in; decreased with a decrease in
51 around the groynes
55 towards the middle of
57 increased by approximately 11 times
63 in a meandering channel
66 in a 60deg spillway
71 are the important
B spell out NTKE and NBSS when first mentioned in the Abstract
C Table 1, Figures 1, 2 and 3 should have citations to the relevant papers in the captions
D In section 2.3 give references for the CFD code. Also refer to the cross-section measurement locations CS0 to 19 in the text.
E In Figures 5 to 10, it would be useful to add labels to the plots (LS1 or Case 1, etc.)
Reviewer 4 Report
The structure of the paper is correct. Nevertheless, some aspects of the paper should be revised and improved:
- The acronyms NTKE and NBSS appear in the abstract. Acronyms must be defined the first time they appear in the text.
- A research paper must be on the frontier of knowledge. What is the scientific novelty of the work carried out? The introduction should be clear about the novelty of the work presented compared to other works already published.
- Many references are cited in the introduction, but most of them [1-15] are not commented in the text. The “Introduction” section clearly needs to be improved.
- Why RNG k-e turbulence model is adopted? The authors should justify this choice in the manuscript.
- Line 105: “to verify the the numerical model”. The manuscript requires careful attention to presentation. The text must be carefully checked in terms of styles and formatting for symbols, equations, figures, tables and references.
- Figure 2 and Figure 3. Is it possible to calibrate the numerical model to get better results?
- The abstract is a summary of the paper, but the "Conclusions" section should not be a summary of the paper. In this section, the authors must specify the conclusions of the research. The authors should complete and improve the "Conclusions" section.
- The authors should check references. For example, reference 25 is incomplete.
To conclude, in my opinion, the paper needs some modifications to be published in a prestigious scientific journal. The authors must clarify the scientific novelty of the work carried out. On the other hand, the authors must complete and improve some sections.
Reviewer 5 Report
The manuscript numerically analyses the effects of groynes placed over a mildly meandering river with regards to the flow pattern, scouring processes and generated turbulence. These kinds of river training structures help directing the flow of water around the bend, mitigating the bottom and bank erosion induced by high flow velocities. Groynes design is a crucial aspect with concern to the effectiveness of such works as they should be low enough so as to be overtopped while enabling a wide flow area, but must be high enough to preserve bending areas.
The manuscript is well written, with a clear message delivered to the reader. The abstract is concise: please define the acronyms and give some results with key concise values.
The literature review is complete and up to date. I would suggest taking into account the following reports:
10.1016/j.advwatres.2018.01.012
to discuss about competing advantages training walls as an alternative to the traditional transverse groynes
10.1080/15715124.2021.1901726
To discuss about the effectiveness of spur dikes in comparison with
Line 84. Specify that u, p and rho are time averaged flow quantities.
Line 85. Is the Reynold stress. Use singular or plural expression.
Line 122. Is 4 m long enough to guarantee fully developed conditions. Please clarify.
Line 139. “When it is observed that the velocity changes negligible and finally the total number of hexahedral meshes is about 880000 was adopted for subsequent simulation.” Please give typical mesh size as well.
Line 316 “The normalized bed shear stress(NBSS) is defined as follows[30]:” check for missing empty spaces throughout the manuscript.
The discussion of obtained results is comprehensive. A resume (e.g. summary table) of pros and cons in using groynes arranged in ascending order would benefit for the sake of clarity.
