# getting results in cfd post

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July 8, 2022, 09:33
getting results in cfd post
#1
New Member

sasha
Join Date: Jun 2022
Posts: 15
Rep Power: 3
Hi everybody!
I simulated an airborne wind turbine(consisting of rotor and stator) in Ansys and solved it by cfx, now I want to evaluate the result but don't know how to get a pressure coefficient plot like the paper's result(I attached the results of the paper). I tried writing this expression in cfd post according to the formula in the reference paper but it was not correct!(attached the formula)

(cp = (Pressure-Reference Pressure )/(0.5*areaAve(density)@(the plane that I want to see the contur on)*((Velocity-blade velocity)^2+ (Radius * abs(omega) / 1 [rad])^2)) )

also, I tried to change it but nothing worked and sometimes I got this error: there is no data in cp! also I don't know which function and location suite for my goal I read cfd post tutorial and found nothing!

this is my first project in Ansys! It would be great if you could help me or send me a relevant context to learn about the topic!
Attached Images
 (810).png (7.1 KB, 17 views) (814).png (42.1 KB, 19 views) (816).jpg (50.9 KB, 14 views)

Last edited by sasha-; July 9, 2022 at 05:01.

 July 8, 2022, 18:20 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,732 Rep Power: 143 The images are not attached. This FAQ might be helpful: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 July 9, 2022, 05:03 #3 New Member   sasha Join Date: Jun 2022 Posts: 15 Rep Power: 3 thank you, I edited the post!

 July 9, 2022, 06:56 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,732 Rep Power: 143 The CFX reference pressure is not (well, at least it should not be) p_inf. I presume p_inf in your equation is the far field pressure. Assuming you have the far field set to zero pressure then p_inf should be zero. The second part of your question seems to say that you cannot generate this variable anyway. In CFD-Post you will need to define it as a new variable (I think that is the third tab), and when correctly defined it will become a variable available like velocity and pressure and all the others. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 July 14, 2022, 13:29 #5 New Member   sasha Join Date: Jun 2022 Posts: 15 Rep Power: 3 hi, thanks for your reply! do you know how can I generate the variable to get a plot like "fig 10" which I uploaded before? to be clear, I don't know how to write the proper expression! I searched and found out people use functions like "areaAve,..." it doesn't seems rational to me as I need to get the result along a line from inlet to outlet and areaAve seems to estimate parameters on a plane! I'm a little bit confused, can you help me?

 July 17, 2022, 21:57 #6 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,732 Rep Power: 143 I would not recommend using CFD-Post to draw graphs like that. I would export the data to python, matlab or whatever you like and do it there. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 Tags cfd - post, cfx