Multidisciplinary Design and Optimization of Variable Camber Wing with Non-Equal Chord

Round 1

Reviewer 1 Report

 

The case studied in this manuscript is a combined elastic and aerodynamic analysis of a quasi-straight rectangular wing with a slightly tapered outer 40% span. The partly wing taper is achieved by sweeping back the leading edge by 3.75 degrees, and the trailing edge is swept forward by 2.00 degrees.

The "structural model" of the analyzed wing is clearly presented with enough details.

However, in the "aerodynamic model," there are some open questions.

The static aerodynamic coefficients are evaluated numerically using an Euler code based on the finite-volume method and adaptive Cartesian grids. Some questions about the viscous calculations ("Friction") are unclear.

·        First, an unfamiliar reader with the "Friction code" doesn't know if it is a 3D boundary layer solver or a Navier Stocks solver.

·        Second, it is not clear if "Friction" solves the entire flow either as laminar or turbulent flow or whether it also calculates the transition zone.

·        Do the authors also require aerodynamic coefficients due to the rate of change?

Moreover, the paper analyzes four flight conditions, as presented in Table 1. It looks like the flight condition "A" gives a cruise flight at an altitude of 1 km. Condition "D" probably represents take-off and landing flight conditions. Condition "B" simulates a small symmetric pull-up maneuver, while condition "C" simulates a combined "exercise" in pitch and roll.

Short comments on the selected flight conditions will enhance the manuscript's clarity.

There are two more issues of interest for either discussion or for assessing their relative importance:

1)      Amount of energy required to deflect the "control panels" from position (1) to the other positions.

2)      I highly recommend adding an assessment of the "real elastic shape" of the wing's skin.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

In this manuscript entitled "Multidisciplinary Design and Optimization of Variable Camber Wing with Non-equal Chord," the authors designed the beam-disk trailing edge deflection mechanism for a non-equal chord wing with the honeycomb composite structure with zero Poisson's ratio as the flexible skin of trailing edge for the variable camber wing, and demonstrated the multidisciplinary optimization of variable camber wing with non-equal chord wing.

 

The novelty reported in the manuscript is the multidisciplinary design and optimization for variable camber wings.

 

The topic is important, and the authors demonstrated many optimization results, but there are several concerns regarding this study that the authors need to clarify.

 

Questions, comments, and suggestions:

 

1) It needs to be clarified what the parameters of the proposed mechanism are.

While the optimization is conducted using some parameters, such as control points, it is not explained why only those parameters are optimized.

 

2) It isn't easy to understand the flowchart shown in Fig. 8. 

 - It is unclear why optimization is started from condition A.

 - It needs to be clarified the next step after optimizing under condition A. A -> D -> B or C? A -> B or C?

 

3) Please provide the parameters used for simulation in Cart3D and discuss the accuracy of the simulation. Also, the parameters of the optimization algorithm used in iSight should be described.

 

4) The reviewer could not understand why the initial values differed for each optimization in section 6(after page 12). It is unclear whether the final optimization results are truly optimal for all conditions.

 

5) In table 8, the optimization result of K is smaller than the initial value. It seems to fail to optimize.

 

Minor comment:

1) Please add parentheses to all references in the text.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript reports a multidisciplinary design optimization of a variable camber wing with a non-equal chord. The variable camber wing is studied in order to determine its optimal members’ sizing with respect to aerodynamic performance and weight. The topic is interesting and novel, however, the innovation needs to be documented and highlighted so that the added value to the literature is sound and clear. According to the reviewer, the manuscript requires a revision before it can be considered for possible publication, as some aspects of the manuscript need to be clarified.

General Comments

11)      Introduction section: The authors must follow a common format for all the references.

22)      Introduction section: It is suggested to present a more extended and more up to dated literature review (only 5 articles are included from the last 5 years). Furthermore, the references documented in the introduction section are just mentioned, while it is expected to demonstrate any weaknesses or limitations of them. In other words, the literature review must be presented in a way that a gap, in the examined research field, is revealed. So that the importance of the work done, in the present manuscript, will be better highlighted.

33)      Page 2 Lines 60-63: The reviewer suggests improving the text and probably the figure so that the description of the wing structure configuration is more comprehensive for the reader. Maybe an additional maximized figure of the trailing edge might be helpful.

44)      Page 2 Line 63: Please briefly explain how the deflection mechanism rotates, what is its excitation mechanism and how it is controlled. – (for completeness purposes)

55)      Page 2 Line 71: the term “two-segment” is proposed to be changed to “two-cell”

66)      Page 2 Line 71: Please provide a few details (e.g. wing span) for the “small UAV” so that the reader can understand easily the size/scale of the wing under investigation.

77)      Page 3 Line 77: The reviewer suggests to the authors to make clear that the entire design/research starts from a baseline design and is tried to be optimized in terms of a)…. B)…. Etc.

88)      Page 3 Line 96: Please explain briefly how the material selection is made.

99)      Page 4 Line 107: Please explain how did you determine the target morphed airfoil geometry.

110)   Page 4, Line 121: Please explain what CST stands for.

111)   Page 4, Line 123: Please explain how did you select the “four typical flight conditions”?

112)   Table, Last column: It is not clear “Airfoil 1 on both sides”? and the rest of this column

113)   Page 5, line 137: please provide references for all software that you have used.

114)   Page 5, line 148: Please explain why zero Poisson’s ratio for the material used is important for this study.

115)   Page 10, lines 227 & 283: Please provide references for all software that you have used.

116)   Page 10, line 282: Please add “g” to the values of the load factors.

117)   Page 11, line 308: Please explain how did you determine the limits of each variable? Did you use any manufacturing constraints?

118)   Page 13, lines 328 & 335: Please provide references for all software that you have used.

119)   Page 15, Line 383: Please comment and explain where the main weight saving is coming from.

220)    Conclusion section: The conclusions must be supported by the results and highlight the most important aspects of the manuscript. The reviewer suggests, the authors to rewrite and extend this section by providing more details for their research.

 

Comments for author File: Comments.docx

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have responded to each reviewer's comments sincerely and revised the manuscript accordingly. However, there are still some unclear parts.

Additional questions, comments, and suggestions:

1) Please add an explanation of why it is necessary to optimize in the order of condition A -> condition D -> condition B -> condition C. For example, what is the purpose of optimizing airfoil shape under conditions B and C after optimization under condition D, which has the most considerable deformation?

2) Please add an explanation on how "optimal airfoil 4" in Fig. 8 is used in airfoil 2 and 3 optimizations. 

3) Is there any particular reason for using Multi-island GA? Using the island model generally increases hyperparameters such as migration rate and strategy. If there is a need to use this type of GA, please provide an explanation.

Minor comment:

1) The resolution of figures 15 to 24 needs to be higher and easier to see. Please replace them with higher-resolution images.

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx