The Effect of the Shear Flow on Columnar Crystal Growth in an Undercooled Melt

Round 1

Reviewer 1 Report

The manuscript may be an interesting addition to the literature but in it's current form I find it very difficult to understand the context of the work or the novelty of the work. Currently the manuscript is almost entirely a list of equations with very little explanation or context provided.

Why is this modelling method required?

What makes the method novel compared to previous methods?

How do the Figures provided relate to the results of the model?

What do the Figures show?

How are the results meaningful to real world applications?

All of this information may be hidden in the manuscript but needs to be highlighted more clearly. You shouldn't have to be an expert in this specific field to understand the manuscript.

Also, one specific technical question, what exactly is the external forced flow? Is this heat flow or something else?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

1. At work, the theoretical introduction is too short. This chapter should be developed and the purpose of the research should be clearly defined. Determine what is new at work.

2. The presented test results correlate with the observations during the actual casting tests. Which I know from experience and from literature.

3. The authors do not detail how to obtain shear forces in a metallic fluid. An inexperienced reader may not understand this work. This should be clearly stated in the introductory section.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

In their contribution "The Effect of the Shear Flow on Columnar Crystal Growth in an Undercooled Melt", Chen et al. report on an approach to determine the shear flow in the aforementioned system. In addition to the presentation of their method, the authors also show the application of this technique to one particular system. In summary, the authors largely focus on the presentation of their approach rather than the applications of this method to specific systems. Becasue the contents of this contribution rather agree with the scope of the mdpi journals Modelling or Methods and Protocols, I strongly recommend to transfer this contribution to one of the aforementioned journals. In addition, there are also certain issues, which should be revised prior to a publication of this work:

- The introduction is very short and does bot provide all relevant information. For instance, why should we focus on this particular field of research? Could the results of this research be relevant for technical applications?

- With regard to the development of the reported approach, certain aspects need to be clearly defined. For instance, it is stated that "the densities of solid and liquid phases are assumed to be equal." Which sort of (thermodynamic) state must be achieved so that this approximation is valid?

- The approach has just been applied to one system; yet, further applications will be necessary to prove the strength of this approach. Furthermore, the authors should also provide certain details regarding the computational resources that were employed.

- To determine the quality of this approach, it will also be helpful to compare the outcome of this research to (experimental) results existing in the literature.

- For the benefit of a better understanding, I strongly recommend to transfer certain steps reported in the Mathematical Methods Section into a sort of appendix.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Paper acceptable for publication.

Author Response

Thank you for your comments.

Reviewer 3 Report

In the revised verison of their contribution, the authors have solved many issues as pointed out by previous review; yet, there is one minor point which could be included as part of an outlook in the Conclusions Section. It will be interesting to apply this approach to materials being different from the example provided in the contribution. Therefore, I recommend to include a statement regarding future work on different systems in the Conclusions Section.

Author Response

Point 1: In the revised version of their contribution, the authors have solved many issues as pointed out by previous review; yet, there is one minor point which could be included as part of an outlook in the Conclusions Section. It will be interesting to apply this approach to materials being different from the example provided in the contribution. Therefore, I recommend to include a statement regarding future work on different systems in the Conclusions Section.

Response 1:

Thanks for the reviewer’s suggestion. We have supplemented a statement regarding future work.

‘The analytical solution of the dynamic model for columnar crystal growth contains the processing parameters during solidification and suggests the definite physical meanings. The splitting mechanism of nuclei revealed by the solution has been testified in the experiment of Cu alloys. The analytical solution provides the prediction of the formation of interface microstructures during solidification through the change of processing parameters. The future work is expected to extend the model for multi-component alloy systems and the applications in a wide variety of alloys such as aluminum alloy and nickel base alloy.’