Unsteady Flow Oscillations in a 3-D Ventilated Model Room with Convective Heat Transfer
Round 1
Reviewer 1 Report
The review
The paper entitled “Unsteady flow oscillations in a 3-D ventilated model room with convective heat transfer” is a study describing the comparison of computer simulation results with the results of a physical experiment. The study analyzed three variants of the ventilated model room, differing in terms of thermal and flow parameters.
The literature review is up-to-date and includes papers that fit the content of the article, the thermal balance is correct and the idea of the experiment is very interesting. However, the following imperfections were highlighted during the review:
The paper contains a large number of charts presenting the research results, however, the authors of the study did not include the necessary substantive discussion about the research results. This should be completed.
The conclusions are not very specific, they do not contain a quantitative comparison of the various options, this should be completed. The conclusions should be pointed out.
The Paper has some grammar errors and gaps were found in the content.
I propose to publish this paper after addressing the above comments.
Author Response
Reply to Q1: thank for valuable suggestions made by this reviewer. We have now revised the manuscript and have tried to include the necessary substantive discussions and reflections about results and findings shown in figures.
Reply to Q2: we agree with this reviewer on further improving the content of conclusion. We have now revised this section by breaking it down to three paragraphs and including more specific quantitative comparisons to reflect those findings seen in the main body of text.
Reply to Q3: as suggested, we have revised the manuscript and have corrected some grammar errors.
Reviewer 2 Report
The authors analyzed the origin and the development of flow oscillation using a 3D ventilated model room. Numerical simulation was implemented using ANSYS Fluent. Computational results were validated using experimental data. Some comments are given to improve the paper:
- Revise the Abstract section. At this moment it describes mostly the study results and is too long. It should be a max of 200 words. In addition, it should start from the need of your research – the general situation.
- The authors must update their literature review. Add analysis of the past 5-10 years old studies. The most recent cited references are from 2014 and 2012. What was done from 2015 to 2022 in this research field?
- Revise quantities explanation after eq. (3). Not all of them have units.
- J (Joules) should be instead of j.
- Quantities used in the equation in subsection 2.3 must be explained.
- Dimensions of the room could be added in Fig. 1.
- In some text places of the manuscript, errors occur regarding the citation “Error! Reference source not found.” The paper should have numbered lines. It would be better to review.
- Something is wrong with the sentence before Table 1.
- Why ventilated room dimensions are selected 2.44x2.44x2.44 m? Usually, rooms have other dimensions and are not cubic.
- How many iterations were used in the simulation?
- The presentation quality of Fig. 7 should be increased.
- Authors should revise the Conclusions section / its structure. Only the main findings could be discussed.
Author Response
Reply to Q1: as suggested by this reviewer, we have made major revision on Abstract and now it is a total of about 200 in alignment with the Journal Guidelines. As for the need of this research, it is difficult to include them in the Abstract due to word limit. However, we do have provided detailed justifications in the Introduction section (see pages 1&2, the first paragraph on the motivation of proposed study).
Reply to Q2: we have cited some recent studies in the field, e.g. references [17, 18, 19].
Reply to Q3: quantities after eq. (3) are standard and can be found in relevant textbook. We have cited a reference [20] to serve for this purpose.
Reply to Q4: we have searched the manuscript but unfortunately cannot found this symbol ‘J (Joules)’.
Reply to Q5: similar to Q3, we have cited a reference [20] to explain quantities used in subsection 2.3
Reply to Q6: we have added the dimensions of the room in the caption of Figure 1 for clarity.
Reply to Q7: this is due to copy/paste original submission to MDPI template. We have now checked the manuscript and have corrected these errors.
Reply to Q8: this is caused by copy/paste to MDPI template. This has been corrected in this revised manuscript.
Reply to Q9: we agree that in general room dimensions are not cubic. However in this study, we choose this ventilated model room of cubic shape, mainly because this model room was previously proposed and experimentally studied by other researchers (e.g. Wang and Chen, [11]). Therefore, we have experimental data available to validate our numerical predictions.
Reply to Q10: due to unsteady nature of flows, it is hard to explicitly define total number of iterations. Instead, we use a fixed time step of 0.055 s (see 2nd paragraph on page 6) and run simulations sufficient long towards ‘statistically-converged’ status. This can be judged by checking whether or not ‘averaged’ quantities have reached ‘mean’ values. For example, we looked at up to 20 successive datasets, each averaging over 5000 iterations (time steps), as explained on page 6 (2nd paragraph). Therefore, maximum total iterations could be 100k, and this varies between cases.
Reply to Q11: as suggested, we have now improved the presentation quality of Figure 7.
Reply to Q12: we have revised the conclusion section with revised structure, i.e. we break the lengthy paragraph into three shorter paragraphs. We also include key findings at the end (also required by another reviewer) and to address potential impacts and beneficiaries of findings obtained in this study.
Round 2
Reviewer 2 Report
Thank you for the revision. Some comments should be revised.
The need of the research should be explained in the Abstract.
Specific enthalpy h* (see explanation after eq. 3) should be measured in J/kgK, not “j/kgK”. Numbered text should be used for the review of the paper.
All notations should be explained in the Nomenclature.
Author Response
1. Comments revised as reviewer suggested;
2. We have included the need of the research at the beginning of the abstract;
3. Unit of cp has been changed as required. We noted text are not numbered properly and this is due to copy/paste to MDPI template by journal manager. We have asked Journal editorial office to fix this problem;
4. We prefer not to include the Nomenclature section, as it is not a compulsory requirement by this Journal (see, e.g. ‘Instructions for Authors’). We also visited some recent published papers in Fluids, and they all do not have the Nomenclature section as well. We prefer to explain all notations in the text instead of putting them under the Nomenclature. For subsection 2.3 on FFT, we decide to remove those equations as they are standard equations. We cite a textbook by Smith so interested readers can refer to that.
