ArticleGust Alleviation by Active–Passive Combined Control of the Flight Platform and Antenna Array for a Flying Wing SensorCraft

Round 1

Reviewer 1 Report

This paper proposed an "active-passive" combined control method for a SensorCraft. The unsteady areodynamic ROM model was implemented to calculate the aerodynamic forces, the effectiveness of the gust alleviation on the platform and antenna array was analyzed and discussed.

I have two comments/questions below:

1) Can you elaborate a little bit more about the CFD validation setup, especially on the boundary conditions used in the CFD simulation? Might be a good idea to add another paragraph to discuss the setup.

2) The ROM seems to work very well in this case. Is the ROM sensitive to the wing geometry or boundaries conditions?

Author Response

1）Information about boundary conditions has been added to the article.

The unstructured mesh is chosen for the CFD calculation, and the dynamic mesh is generated by the spring smooth method to accommodate the dynamic deformation of the boundary. The outer boundary is set as the pressure far-field boundary condition, the wing surface is set as the wall boundary condition, the near-wall mesh is encrypted, and the mesh number is about 520,000. The Mach number is 0.9, the angle of attack is 0°, and the time step is 0.0001 s. In the CFD calculation process, the function of each order of modal vibration is obtained by polynomial fitting, and the variation of the vibration pattern with time is loaded into the CFD program.

2）The ROM is not sensitive to the wing geometry or boundaries conditions.

The identification of the kernel function is the key to construct the Volterra model. Various methods have been developed to identify the kernel function, such as impulse response method, step response method and frequency domain response method. In this paper, the first-order kernel obtained by the step response method contains part of the second-order kernel components, which can reflect more nonlinear characteristics and has better numerical stability.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript can be accepted for publication after minor corrections.

Author Response

Thank you very much for your suggestion, the manuscript has been revised.

Reviewer 3 Report

Authors have fixed all my comments. The paper is ready to be published.

Author Response

Thank you very much for your comments, the manuscript has been revised.

Reviewer 4 Report

Dear Authors,

The proposed manuscript deals with very interesting issues and is multidisciplinary. At least two separate publications can be prepared from its contents. As the authors, you have decided on a rather difficult task which is to combine the content on aerodynamics, CFD, with issues related to strength and deformation, control theory, and finally antenna technique! I believe that you have succeeded, however, and above all, the logical sequence of considerations has been preserved.

On line 45 there are references to many sources. The order of citation is not maintained - there are no references to items 6-9 and 12. It is not advisable to cite too many works in one place, each of them should be referred to in at least one separate sentence.

There are no units in the descriptions of the axes in the drawings 7a-c (timesteps - are they discretization points, or is it time, e.g. in seconds? The same remark applies to the generalized aerodynamic force), figure 8 (a is clear but in b flutter frequency ratio is dimensionless? If so, maybe it's worth specifying [-] for dimensionless values?) The way of marking the units in Fig. 11 is quite unconventional - "Time / s"? The same applies to Fig. 13. This and the previous remark apply to almost all subsequent graphs in the manuscript.

The list of SensorCraft features should be constructed in the form of, for example, a bulleted list. The form of content presentation in lines 36-41 is unacceptable.

How were the characteristics (figure 19) determined for individual deformations? Was the method described in paragraph 3.8 applied directly, or was ready-made software used? The same applies to Fig. 20.

Best regards,

The work is written in an understandable way, I did not notice any significant linguistic errors.

Author Response

1）The citation in line 45 has been modified according to your comments.

2）The timesteps in the drawings 7a-d are  discretization points, and the generalized aerodynamic force is dimensionless. The flutter frequency ratio in figure 8b is dimensionless. Change "Time / s" to "t / s" in  all subsequent graphs. 3）The list of SensorCraft features has been constructed in the form of a bulleted list. 4）There is no ready-made software available. The deformation features are extracted by home-made program based on the method described in paragraph 3.8.

Author Response File: Author Response.docx