Performance of a Closed Cycle Power Takeoff for a Shore-Based Wave Energy Device

Round 1

Reviewer 1 Report

The research presented in the reviewed article concerns the oscillating water column in which the wave power is transferred to an airflow that rotates a turbine. The subject matter of these studies is exciting and related to current trends in renewable energy sources. The works discussed in the article represent a high substantive level.

Unfortunately, the authors did not avoid a few errors/shortcomings. Some of them are marked directly in the article, others are presented below: 

1. I think the entire summary should be rewritten. The main task of the abstract is to encourage the reader to read the article. On this basis, he is to evaluate the content of the article. There are a lot of mental shortcuts and understatements in the current version of the abstract.

2. Publications no. 3, 4, 6 and books: 11, 12: Each publication referred to by the authors should be discussed separately. Each of these publications should be discussed separately in a few sentences, specifying what it concerns, what conclusions can be drawn from it, and how it differs from the others.

3. A list of acronyms used by the authors should be added.

4. Explanations of the symbols used in all formulas should be added.

5. Please improve the quality of the descriptions in Fig. 2. They are illegible.

6. In Fig. 7 and Fig. 8, the quality of the descriptions should be improved. They are illegible.

7. Line 285: Did the authors mean parallel computing on several cores/computers?

However, these errors do not affect the substantive quality of the article. I believe that the authors' consideration of my comments will improve the article's readability.

Comments for author File: Comments.pdf

Author Response

1.1         The abstract has been tidied up and the focus sharpened.

1.2         The introduction has been expanded somewhat and each reference discussed individually.

1.3         A list of nomenclature has been added at the end of the paper.

1.4         the meaning of symbols is explained in the text as they are introduced and a list of nomenclature has been added at the end of the paper

1.5         The font has been increased and the scale of the figure has been increased as well.

1.6         The font has been increased and the scale of the figure has been increased as well.

1.7         The wording has been changed in the text. (new line 305)

Comments on PDF          edits corrected

Reviewer 2 Report

In my opinion, the manuscript entitled “PERFORMANCE OF A CLOSED CYCLE POWER TAKE OFF FOR A SHORE-BASED WAVE ENERGY DEVICE” should be accepted for publication after the authors address the following minor points:

1.       For the use of the “idealized model” with the Mutriku conditions, the authors should report the values of the parameters Ci and Cf in Eqs (9) and (14), respectively.

2.       For the CFD simulations with the Mutriku conditions, the authors should provide more information about which CFX options they selected, they should report grid and temporal resolution data, and more details about the grid independence study they mention.

Minor editing is required.

In the title, the correct is "SHORE-BASED"

Some other examples. The correct expressions are: L. 75, "with the Mutriku breakwater", L. 184, "of the month of April".

Author Response

Reviewer 2        

2.1         Values added in the text.

2.2         The simulation is s a steady state based on Mxing Plane Model, so there is no temporal resolution. Extra details on the simulation setup are added to the text (around line 300). A new subsection (2.5) is added to describe the convergence study undertaken.

2.3         Yes, this has been corrected.

2.4         These have been corrected.

Reviewer 3 Report

The manuscript is in good form, yet can still be improved before publication. The detailed comments are listed below:

1. In the title, "Power Take Off" should be "Power Take-off", "OF" and "FOR" should be "of" and "for".

2. The literature review needs to be significantly extended to make it more comprehensive.

3. Please explain what is q_T used in equation (4).

4. For the rotor blade speed U, is it the tip speed?

Author Response

Reviewer 3        

3.1         Corrected

3.2         The introduction has been expanded somewhat and each reference discussed individually.

3.3         explained in the text (line 131) and a list of nomenclature has been added at the end of the paper

3.4         U is the translational speed of the blade at mean radius. This has been added to the text (line 248).