getting results in cfd post

sasha- · July 8, 2022, 10:33

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!

ghorrocks · July 8, 2022, 19:20

The images are not attached. This FAQ might be helpful: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F

sasha- · July 9, 2022, 06:03

thank you, I edited the post!

ghorrocks · July 9, 2022, 07:56

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.

sasha- · July 14, 2022, 14:29

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?

ghorrocks · July 17, 2022, 22:57

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.

July 8, 2022, 19:20		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	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, 07:56		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	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 17, 2022, 22:57		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	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.

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July 9, 2022, 06:03		#3
sasha- New Member sasha Join Date: Jun 2022 Posts: 17 Rep Power: 4	thank you, I edited the post!

July 14, 2022, 14:29		#5
sasha- New Member sasha Join Date: Jun 2022 Posts: 17 Rep Power: 4	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?