VSPAERO, Disk model method

[Inseo Choi]

As I known that, vspaero's disk model is based on Conway Actuator disk thoery, and johnson disk theory.

I curious about disk model's velocity components calculation way.

When I check vspaero.RotorDisk.C source code, I can find 'Velocity_T', 'Velocity_X' and 'Velocity_R'.

Is rotor velocity just superpostion with free stream(V_inf) ?

Is there any way to check velocity field infront of wing section ? 

As I known that, Disk stream tube is going narrow when far from disk by momentum theory.

So I think that the vinf+rotor velocity filed is not fit with disk diameter on wing section

Can I export complex velocity field to check this problem ?

Thank you.

[Rob McDonald]

The latest version of VSPAERO includes the ability to generate slice planes and visualize them in the viewer.

In this case, an actuator disk was placed in front of a Pod and analyzed in Panel mode (thick body).  The velocity vectors in front of the disk (to the right) can be seen contracting before the disk.  Behind the disk, the swirl component causes the top vectors to be prominent, while the lower vectors vanish into the plane.

The Conway solution gives the velocity _everywhere_ caused by an actuator disk.  It gives the velocity in front of, behind, or to the side of the disk.

In this solution approach, the actuator disk contributions are held constant and are added to the freestream contribution.

Rob

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[Inseo Choi]

Hi Rob.

Thank you for your response to my questions.

I have some question again.

Is there a way to maipulate number of velocity point ? I had only 16 veolcity points

I'll try check this velocity contour infront of the wing behind the disk.

As I've understood, swirl velocity caused by rotating disk effect on free stream velocity just adding each velocity componets.

I got it now. Thank you.

2022년 8월 17일 수요일 오전 1시 52분 38초 UTC+9에 Rob McDonald님이 작성:

[Rob McDonald]

The survey points are adapted to the body -- so a disk in isolation doesn't seem to trigger any adaptation.  I don't know a way to force more resolution there.  I will ask.

I added a pod to mine to make sure something interesting would be resolved.

You can also survey the velocity at any desired points.  Search the mailing list for how to add a list of points to survey to the input file.

Rob

To view this discussion on the web visit https://groups.google.com/d/msgid/openvsp/4b176936-7422-4b6e-b2a2-43549e1fe42dn%40googlegroups.com.

[Inseo Choi]

Hi Rob.

I searched the mailing list about how to add a list of points to surveying velocity

https://groups.google.com/g/openvsp/c/KqP3XrMXTg0/m/GHN22jvlAAAJ

https://groups.google.com/g/openvsp/c/S5KL0Cxy8W4/m/gL3PWnWWAwAJ

https://groups.google.com/g/openvsp/c/8TF3DCy7BWA

So I found the way about  the velocity filed position which I want, is using cmd prompt vspaero.

https://www.youtube.com/watch?v=5e_crTyH-uM

I followed up this video for using cmd vspaero, and I add the line "NumberofSurveyPoints = N" and position.

ex)

NumberofSurveyPoints = N

1 x1 y1 z1

in my code)

NumberofSurveyPoints = N
1 1 1 1

vspaero is running well, but the *.SVY file wasn't my folder

Is there any other way to survey specific velocity ?

2022년 8월 17일 수요일 오전 3시 22분 31초 UTC+9에 Rob McDonald님이 작성:

[Brandon Litherland]

Depending on how you ran VSPAERO from the command line, your SVY file could have ended up with the vspaero.exe application.  When you run VSPAERO from the GUI, the command that runs the program is the first line of the output where you normally see solver progress. Scroll to the top to find this line.  If you manually add the survey points to your vspaero input file, then run the command as printed with quotations in the command prompt, it should save the SVY file in the same directory as your model.

[Inseo Choi]

Brandon and Rob,  Thank you very much.

It's worked out when I add 

"NumberofSurveyPoints = 1
1 1 1 1
interrogate"

under the line "NumberOfControlGroups = 0" in .vspaero script.

I'll make velocity contour using this way about propeller wing interaction.

-Inseo-

2022년 8월 18일 목요일 오후 10시 11분 30초 UTC+9에 litherlan...@gmail.com님이 작성: