Influence of Density Ratios on Richtmyer–Meshkov Instability with Non-Equilibrium Effects in the Reshock Process

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors study thoroughly the RM instability and draw useful conclusions regarding the non-equilibrium effects during the reshock process from mesoscopic to macroscopic levels. Richtmyer-Meshkov (RM) instability is caused by the shock wave on the interface between two fluids due to discrepancy between the density and the pressure gradients. This RM instability is studied by  checking numerically the trends of the density gradients, the global physical gradients and the local macroscopic physical gradients. The authors present systematic graphs of the propagation of the phenomenon with time demonstrating also the thermodynamic non-equilibrium behavior.

Their findings contribute to the understanding of the mechanism of RM instability including the scale effects.

The paper is useful for the study of the aforementioned instability.

Comments on the Quality of English Language

NONE

Author Response

Thank you for your support.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In the article, the authors deal with selected aspects of the influence of parameters on the course of the Richtmyer-Meshkov instability process. It is impossible to analyze all the authors' considerations on this topic in the time-limited review process. Therefore, the reviewer, based on the authors' scientific achievements, believes that the article is worth publishing and will be of interest to a close circle of researchers. However, below are some comments that come to mind after reading the article. I submit these comments to the authors' analysis.
1. The authors use a rather complicated, multi-index, multi-parameter system of writing physical equations, which may be illegible, especially for people who do not deal with this subject. Therefore, I propose to introduce a list of nomenclature of all symbols along with their description and units. Ambiguity example, Eq. 9, "the symbol ηi is used to describe the internal energy". If it's energy, why is it added to speed?
Eq. 11, 12 "D and I that represent the spatial dimension and extra degrees of freedom". What is this physical quantity, what is its dimension?
2. The same applies to charts. Physical units need to be introduced; in their current form, charts are a different kind of abstraction, not understandable to everyone.
3. The authors present only the results of simulation tests. However, they provide too few details for other teams to verify their results. Moreover, there are no references to experimental verification confirming the numerical hypotheses.
4. The conclusions are very general. However, the problem under consideration concerns physical issues, so the conclusions should not only concern the numerical experiment, but should translate into conclusions regarding real processes. How will research expand cognitive knowledge about the world, and how will it translate into physical applications?
5. In the introduction, the authors use wholesale citations, such as [18-35]. This, according to the reviewer, is inelegant and provides little information. You should refer to the specific content of the article for a specific purpose.

Author Response

We would like to express our gratitude for your diligent review of our manuscript and for sharing your insightful comments. 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this paper, the Richtmyer-Meshkov instability in the reshock process with various density ratios is investigated through the two-component discrete Boltzmann method. The authors analysed both the thermodynamic non-equilibrium and the hydrodynamic non-equilibrium effects, and obtained a linearly increasing relationship between the time integration of the global average densities and the density ratio. The authors also found that the first physical mechanism is that the areas of density gradients are extended as the mixing of the two components accelerates under the action of the shock wave. The second physical mechanism is that the global physical gradients reduce while the transmitted shock wave and transverse waves leave the calculation domain, and lastly, the local macroscopic physical gradients decrease when the fluid structure gradually disappears due to the dissipation and diffusion.

The following remarks are to be addressed:

1) There are some typos that should be corrected.

2) Too much abbreviations can be seen in this paper. The authors should reduce and avoid too much abbreviation of words (shortcut of words). Most of the readers will face difficulties in reading and understanding the content of the paper because of these abbreviations.

3) I do not see a real comparison of the obtained results in this paper with previous ones.

If all these remarks are taken into consideration, the paper can be accepted for publication in Inventions journal.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Thank you for dedicating your time to review our manuscript and providing your valuable comments. We have considered each of your suggestions and provided detailed responses accordingly. We try our best to improve the style and grammar, thank you very much. 

Author Response File: Author Response.pdf