Analyzing Richtmyer–Meshkov Phenomena Triggered by Forward-Triangular Light Gas Bubbles: A Numerical Perspective

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents a high-fidelity numerical study of Richtmyer-Meshkov (RM) phenomena initiated by shock waves interacting with forward-triangular light gas bubbles. The authors examined the effects of Atwood number and shock Mach number on flow evolution using a discontinuous Galerkin technique to solve a 2D compressible Euler system. Overall, this is a well written paper, the methodology is well chosen and the computational model and numerical method are all clearly presented. Moreover, the authors validated the simulation accuracy against experimental data and found really good agreement which significantly boosted the confidence of the research. The author also did a Thorough analysis of Atwood number and shock Mach number effects on RM phenomena and a detailed examination of vorticity formulation and bubble interface evolution for each case.

However, there are a few things that may need attention. First, the research motivation may need more justification. Previous numerical investigation on this topic already covered non-polygon interfaces, including cylindrical, spherical and elliptical bubbles, as well as polygon bubbles such as square bubbles. It is not particularly clear for me, is this configuration of particular importance compared to others or whether it can shed additional light to this already well researched field. The author may need to consider the difference of this research compared to previous ones. Second, the author may consider including heavier gases to include larger Atwood numbers for a broader perspective on density ratio effects. Last, “similar speed” on line 11 should be removed.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper has studied the effect of shock waves with forward-triangular light gas bubbles on the Richtmyer-Meshkov phenomena, using CFD under different shock Mach numbers near the Atwood number. The work is novel and interesting, including fluency in describing discussion around the results which has led to the attraction of readers and is also beneficial for the relevant community. 

In addition, the method has been validated. 

However, some recommendations can improve the quality of the paper and robust the work which should be considered before publication. Those are as follows:

1- Due to the variety of parameters the paper should involve nomenclature. It helps readers be less confused when meeting the abbreviations. It can boost the pace of their reading, making text more readable, and reducing readers' back and forth along the text.

 

2- In the introduction part, the novelty of the work should clearly and directly be expressed to showcase the distinguishing feature of this paper from other works. I recommend writing this by the end of the introduction. 

3- A section should be designed to put the analytical and calculational formulations in. I can observe that the authors have introduced the Atwood number in the introduction line 110, and other equations such as Eq (20), Eq (21), and Eq (22). Please define a new section and place those types of formulations in that part.  

4- The temperature change plays a pivotal role in vortex generation for different types of gases and affects the structures of vortices which can be factored in line with Atwood and Mach number. Hence, it is better to be taken into consideration.  

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have addressed all recommendations, therefore the paper is suitable for publication.