Surge Response Analysis of the Serbuoys-TLP Tension Leg Platform under the Action of Wave–Current Coupling
Round 1
Reviewer 1 Report
See attached file
Comments for author File: 
Comments.pdf
Author Response
Dear reviewers,
The authors would like to thank the reviewers for their constructive comments which have helped to improve the manuscript significantly. Please open the revision mode in the revised manuscript to correspond to the line number. Our responses to the questions are provided below (typed here in red) following each question.
Author Response File: Author Response.pdf
Reviewer 2 Report
The proposed manuscript presents a study of surge response analysis of Serbuoys-TLP tension leg platform under the action of wave-current coupling. The idea of placing buoys in the middle of tendons of a TLP is interesting. Before numerically analyzing the motions of the proposed Serbuoys-TLP in waves and currents, the authors carry out validations of their numerical models. They also carry out experiments and compare the results with their numerical results. I judge the subject of the manuscript is interesting from the academic viewpoint and it will contribute to the development of new TLPs of better performance as well.
However, I have some comments and questions as I describe in the followings, to which, I recommend, the authors pay due consideration and revise the manuscript accordingly.
- First of all, beside the numerical facts, it needs to be explained from the viewpoint of physics why the surge response is suppressed when buoys are placed in the middle of tendons.
- The term ‘wave-current coupling’ appears frequently and it seems to be one of the main subjects of the authors’ study.
However, it seems in the manuscript that ‘wave-current coupling’ merely refers to the change of wave encounter frequency due to currents. I understand the change of wave encounter frequency due to currents is just one of the coupling effects. For example, it is well known that a ship advancing in waves suffers additional steady wave loads, which cannot be explained with the modulation of encounter frequency of the ship against waves only. Therefore, it should be stated explicitly in the manuscript that, among various possible effects of wave-current coupling, only the change of encounter frequency with waves due to currents is taken into consideration and why. By the way, to be more specific, in what way the change of encounter frequency is accounted for in the numerical evaluation of wave forces?
- Miscellaneous matters
(1) Page 1, Line 41.
It is described that the currents affect the wave steepness as well as wave period. Is the modulation of ‘wave steepness’ taken into account in the authors’ work, and, if so, how is it accounted for?
(2) Figure 1 and Figure 2
In Figure 1, the TLP is supported with two tendons while the TLP depicted in Figure 2 is supported with a single tendon. Which one was actually subjected to the authors’ analyses? By the way, Equation (8) seems to be suggesting that the number of tendons of the TLP subjected to the authors’ numerical analyses is 4.
(3) Fig.2 and Fig.3
The depth of the origin of the coordinate system depicted in Figure 2 and that depicted in Figure 3 are not the same. As shown in Figure 2, if the origin of the coordinate system is placed on the sea bottom, Equation (2) does not hold, because, for example, according to Equation (2), U(d)=2U(0).
(4) Page 3, Line 100-101.
It is said that ‘d is the length of the tension tendon’, but, I think it should be ‘d is the water depth’.
(5) Page 4, Line 116 and Page 11, Line 292.
The term ‘natural frequency of the wave’ is not an appropriate expression since ‘natural frequency’ usually refers to resonant frequency of a certain oscillating system. ‘wave frequency in the absence of currents’ may be more appropriate, for example.
(6) Equations (8), (10).
It is said that the damping coefficients in Equation (8), (10) include viscous damping, but the damping terms in the two equations are assumed to be proportional to velocity, whereas I understand viscous damping is usually expressed in the form proportional to velocity squared, velocity times absolute value of velocity, to be more precise..
(7) Page 9, Line 254.
What is ‘return stiffness’?
(8) Page 13, Line 331.
The term ‘negative connection’ is not an appropriate expression. It should be, for example, ‘negative correlation’.
Author Response
Dear editor and reviewers,
The authors would like to thank the reviewers for their constructive comments which have helped to improve the manuscript significantly.Please open the revision mode in the revised manuscript to correspond to the line number. Our responses to the questions are provided below (typed here in red) following each question
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Revision 1: “Surge response analysis of Serbuoys-TLP tension leg platform under the action of wave-current coupling”
The authors have addressed the majority of the comments of the reviewer by (i) adding clarifications and updating sentences, (ii) providing more information (e.g. run an extra cases for larger current velocities), (iii) generating new figures and tables, and (iv) improving the introduction and conclusions. These updates and new material shed light on the underlying physics of the presented results and help explain the observed trends better.
Overall, the aforementioned changes increased the size of the manuscript by 5 pages and improved its quality, increasing its value for the reader. This is a testament of the authors’ sincere effort to address diligently the comments of the reviewers. So, thank you for your effort.
The reviewer has only three minor comments, as shown below, which the authors can address easily. Therefore, the manuscript is suggested to be accepted for publication with minor revisions.
Minor comments:
- Line 55-56: Replace the phrase “when wave-current coupling was considered and not considered” with “when the wave-current coupling was considered, relatively to the case that it was not considered”.
- Table 2: The time is in seconds correct? If this is the case, then please update the title of the 2nd column and say “Time to solve (s)”.
- Line 456: Delete the phrase “there is”….since it is not needed.
Author Response
Dear reviewer,
The authors would like to thank the reviewers for comments that made the presentation of the manuscript more accurate. The revised version of the article has been completed after taking 1 days nearly, please open the revision mode in the revised manuscript to correspond to the line number. Our responses to the questions are provided below (typed here in red) following each question:
Reviewer: 1
Revision 1: “Surge response analysis of Serbuoys-TLP tension leg platform under the action of wave-current coupling”
The authors have addressed the majority of the comments of the reviewer by (i) adding clarifications and updating sentences, (ii) providing more information (e.g. run an extra cases for larger current velocities), (iii) generating new figures and tables, and (iv) improving the introduction and conclusions. These updates and new material shed light on the underlying physics of the presented results and help explain the observed trends better.
Overall, the aforementioned changes increased the size of the manuscript by 5 pages and improved its quality, increasing its value for the reader. This is a testament of the authors’ sincere effort to address diligently the comments of the reviewers. So, thank you for your effort.
The reviewer has only three minor comments, as shown below, which the authors can address easily. Therefore, the manuscript is suggested to be accepted for publication with minor revisions.
Minor comments:
1.Line 55-56: Replace the phrase “when wave-current coupling was considered and not considered” with “when the wave-current coupling was considered, relatively to the case that it was not considered”.
Thanks to the reviewers for their suggestions, which makes the authors' meaning more understandable to the reader. The author has revised the sentence in the manuscript (See Line 53 to Line 54).
when the wave-current coupling was considered, relatively to the case that it was not considered.
2.Table 2: The time is in seconds correct? If this is the case, then please update the title of the 2nd column and say “Time to solve (s)”.
As the reviewer said, the time in Table 2 is in seconds. Thank you for your careful review, and the authors have revised the title of Table 2
3.Line 456: Delete the phrase “there is”….since it is not needed.
Thanks to the reviewers for their suggestions to make the grammar in the manuscript more accurate, and the authors have made changes in the manuscript (See Line 433 to Line 434).
In pure wave condition, a negative correlation was found between suppression efficiency λ and wave height or period.
Author Response File: Author Response.pdf
Reviewer 2 Report
I have no further comments.
The revised manuscript can now be accepted for publication.
Author Response
Dear reviewer,
Thank you for your approval of this paper. Your first round of comments helped a lot in this paper. Thank you very much for your efforts.
Best wishes to you
Author Response File: Author Response.pdf
