Study on Dynamic Lubrication Characteristics of the External Return Spherical Bearing Pair under Full Working Conditions

Round 1

Reviewer 1 Report

The subject of this paper is surely interesting, from both the technological and theoretical points of view. Nevertheless, the presentation needs a wider context to improve the clarity of statements. The abstract poorly describes the problem itself, while it anticipates several results. A better balance between focus of the paper and relevant outcomes is highly suggested. The language looks somewhere cryptic, and thus understanding of contents suffers. Introduction even shows a lack of description of the domain context, to identify the system under investigation, goals of analyses and motivation of this paper. Authors assume that readers just work on the same research area, and specifically on this subject. A little introduction of at least some sentences is recommended. Section 2 similarly starts with a very detailed analysis without describing the system and its behaviour.  Despite the consistency of contents, their presentation is too schematic, to be clear. Description even suffers of several repetitions, making the statement quite heavy to be analyzed. (In Eq.(5) symbol Ve at denominator should see “e” as a subscript). Figures in section 2 superpose many elements, leading to a difficult reading. Particularly, figure 4 concentrates information into a small sketch.  In general, the rationale is fluent, despite its too schematic presentation. In section 4 (row 242) it looks surprising reading some numerical figures about a system whose properties were never described before. The following sections introduce the mathematical models and numerical results. Since section 3 states that the whole paper is aiming at describing the behaviour of the system designed by the Authors, a preliminary set of experimental evidences should be welcome, especially to quote the numerical results described in section 3, whose detectability looks rather hard to be assured. In general, a clearer comparison between the original work herein presented and existing models in the literature should be better proposed. A deeper discussion about the generality of results herein presented should be demonstrated and a little bit more stressed. Some doubts about the references arise, since they are quite a lot focused on few authors.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Review Comments:
1.The abstract should be revised. The significances in engineering field should be highlighted.
2.The authors are suggested to explain the novelty of the paper.
3.In Section 2, the authors are suggested to add a diagram or picture of the flow chart of the procedure. 
4.It is better to add contents about the algorithm, the differential regime, the convergence accuracy and the robustness of the calculation.
5.For the lubrication characteristics in Section 3.1, further step analysis should be added. The authors are suggested to add comments as well as the references below. These references clearly illustrate the lubrication regimes as well as the lubrication characteristics on the interface. They are closely related with the present research. 
[1] Theoretical and experimental exploration on the micro asperity contact load ratios and lubrication regimes transition for water-lubricated stern tube bearing[J]. Tribology International, 2021, 164: 107105
[2] Analysis on the Lubrication Performances of Journal Bearing System Using Computational Fluid Dynamics and Fluid–Structure Interaction Considering Thermal Influence and Cavitation[J]. Tribology International, 2013, 64: 8-15.
[3] Theoretical and experimental exploration into the fluid structure coupling dynamic behaviors towards water-lubricated bearing with axial asymmetric grooves[J]. Mechanical Systems and Signal Processing, 2022, 168: 108624.

6.For the conclusions, it is a little long. Several brief points of conclusions are enough. The authors are suggested to rewrite the conclusions.
7.The English should be improved considerately.

Major revision.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thank you for your careful editing and compliments.

Reviewer 2 Report

The authors have revised the paper carefully point by point. It can meet the requirement of the journal now. The reviewer suggest to accept it for publication in its present form. Accept!