Review Reports

Round 1

Reviewer 1 Report

please see attachment.

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper analyzes laminar natural convection in a triangular enclosure by means of the lattice Boltzmann method with the multiple relaxation time approximation. All neceserry parts for numerical work are included. I suggest to address the following comments before the final decision:

1. The authors should highlight the scientific novelty of their work in the Introduction. Moreover, there is no transition between literature review and aim of the work which interrupts the reading flow 
2. The studied range of the Rayleigh number should be discussed. In what engineering application is this range encountered?
3. More careful comparison with the results of Mejri et. al. [Ref. 16] should be performed. If the MRT LBM model reproduces the same patterns as the SRT LBM, why do we need to use more complicated and more numerically expensive MRT model under studied conditions?  

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

In this paper, the authors have used MRT-LBM to investigate laminar natural convection in a triangular cavity. The solver is qualitatively verified with data from literature. The method presented is not new and the results obtained are of some interest to the community. The manuscript, however requires extensive editing in terms of more results and analysis for it to be considered for a publication in the present journal. Therefore, I do not recommend this article. The following major concerns may be considered by the authors if they wish to submit an extensively edited version of the manuscript.

Major Concerns:

1. Only steady and laminar results are presented, these are too primitive. Could the authors please explore unsteady and chaotic regimes as well?
2.  Different symbols should be used for indicating lattice velocity vectors in the context of D2Q9 and D2Q5.
3. Classical LBM is limited to uniform and Cartesian meshes, it is not clear how the inclined wall is treated in the simulations. Please provide more details regarding the wall treatment. Further, a figure showing the mesh used could be presented.
4. It is not clear how the bounce-back boundary condition was applied on inclined wall. 
5. Streamlines can be plotted with arrows to know the flow directions.
6. The Grid sensitive study is performed at Ra = 10^4. The chosen mesh is used for higher Rayleigh numbers also. Usually, the grid-sensitive study is performed at a higher Rayleigh number, and the same mesh can be used for lower Rayleigh numbers. But not the other way around.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have revised the manuscript. It  can be published.

Reviewer 2 Report

The authors discussed all comments and suggestions. However, the authors should carefully think about engineering applications for their work. I don't feel that solar collectors can have triangular shape. 

Reviewer 3 Report

The authors have sufficiently addressed the concerns raised by the present reviewer. Therefore I recommend this manuscript for publication.