Frequency and Time Domain Simulations of a 15 MW Floating Wind Turbine Integrating with Multiple Flap-Type WECs

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study focuses on the semi-submersible wind-wave combined power generation platform. There are some detailed suggestions aimed at enhancing its innovativeness and overall quality.

1) To enhance the paper's credibility, more extensive validation and verification of the proposed model and methodology could be conducted. This could include comparisons with experimental data, sensitivity analyses, and uncertainty assessments.

2) While the paper focuses on maximizing wave energy capture, it could also incorporate multi-objective optimization techniques to balance efficiency, cost, environmental impact, and system reliability. This would provide a more holistic approach to system design and analysis.

3) The paper should more explicitly state its research novelty in comparison to existing work. A more concise summary of the existing research and a clearer articulation of the research gap that the paper aims to fill could be more clearly included in the introduction.

4) The cited references could be more up-to-date, it is suggested to include more recent references, e.g., S. Huang et al., "Robust Distributed Fixed-Time Fault-Tolerant Control for Shipboard Microgrids With Actuator Fault," IEEE Transactions on Transportation Electrification, doi: 10.1109/TTE.2024.3411289.

5) The paper should discuss its limitations and suggest directions for future work. This would not only acknowledge the current state of the research but also stimulate further investigation and collaboration in the field.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript investigates the performance of a hybrid wind-wave platform consisting of a 15MW floating wind turbine and three flap-type WECs by both the frequency and time-domain models. This paper is well-written and covers a wide range of topics including multi-body hydrodynamic interactions and the coupled analysis of the integrated system by using the well-proven F2A method. However, there are still some minor issues that need to be addressed by the authors:

[1] The literature review is not comprehensive enough. There are some recent review articles discussing about the joint utilization of wind and wave powers. Plenty of studies have been published in this area on the conceptual design, analysis method and experiments. Therefore, the authors are suggested to provide a more in-depth literature review to identify the research gap and the novelty of the present study.

[2] The citation format of the references is not correct and not consistent through the whole paper. When the number of authors exceeding 3, the direct citation should be “xx et al.”. If only 2 authors, should be A and B. In addition, in the reference list, the authors should be all listed.

[3] The use of “FAST” and “OPENFAST” is confusing. The authors should make clear that AQWA is dynamically coupled with which software (FAST or OPENFAST).

[4] Figure 10 compares lots of parameters, which is suggested to divide into 4 figures to show the comparison of added mass coefficient, added damping coefficients, wave forces and RAO, respectively. In addition, as the dimension of the flap-type WEC is much smaller compared with the floating foundation. Thus their impact on the hydrodynamics of the floating foundation is minimal as shown in the comparison in Figure 10.

[5] In section 2.1.2, the time domain model is based on AQWA’s time domain simulation. Thus the general theory and numerical integration algorithm should clearly following AQWA’s time domain theory. The authors can cite the AQWA’s time domain theory or other references such as “A fully coupled time domain model capturing nonlinear dynamics of float-over deck installation”.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Due to the increased problem of global warming, the use of alternative energy sources is gaining more and more relevance. Of particular interest are wind turbines that have good efficiency and high-power output. Sea wave energy converters into electricity are also of great interest. Combining these two types of sources is a logical solution, because by selecting the optimal location of the combined wind generator and wave generator on a floating platform, it is possible to significantly increase the efficiency of the generator. Of course, it is necessary to optimize the design, to determine the possible mutual influence of the two types of generators. Therefore, the relevance of this work is beyond doubt.

The peer-reviewed paper consists of an introduction, three original parts and conclusions (five sections in total).

In the introductory part, the authors presented the existing models for analyzing the interaction between wind turbines and wave generators based on the review of 23 literature references. In the second section (Materials and Methods), different theories for calculating hydrodynamic loads are presented. The third section presents the authors' proposed platform model for combined wind and wave power generation. The fourth section (erroneously numbered by number 3, although the further numbering of subsections is correct) is devoted to the results of modeling the combined platform. It contains the main results of this paper. In the final part, the authors conclude that combining wind and wave platforms has little effect on the parameters of the floating platform, although this solution partially improves the stability of the combined platform in roll, pitch and yaw.

From the physical and mathematical point of view, both the mathematical model built by the authors and the results of numerical analysis look absolutely correct. I would reduce the number of figures (or put them in supplemental materials), but I leave that to the authors' discretion.

In this paper, I found 12 self-citations [Yang Y.– 2 (15,16), Chen M. – 10 (2,3,4,17,18,21,25,26,28,31)] with a total of 35 literature references. That's 30%, which I think is too many. It happens that there are very few scientists in a certain field of research, but this is not the case for me. However, I would reduce the number of self-citations in the introductory part, but this recommendation is within the competence of the esteemed editor.

Taking into account the correctness of the mathematical model proposed by the authors, the accuracy of the calculations and the importance of the results, in my opinion, this paper can be published without significant changes.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

1. There is an important point should be improved more. In the revised version of the manusript,  the introduction should include a clearer statement of the research problem, the research gap in the existing literature that the paper aims to address, and the main contributions.

2. The presentation form of the revised version of this paper is very confusing, and the revision mode adopted by the PFD version cannot distinguish the revised content. It is recommended not to use the revision mode, but to highlight the revised sentences or paragraphs.

In summary, the quality of this manuscript should be improved more and more.

Author Response

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Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

No more comments.