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Old   February 7, 2017, 18:50
Default RAE2822 convergence
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Zhihao Ding
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Hi all,

I have some problems with the testcase "rae2822". The original case is the case 6 of RAE2822 and it works well.

But when I am trying to study the case 9 by only modifying the mach number and the angle of attack (0.734 for Mach and 2.79 for angle of attack), the solution can be poorly convergent and not stable at all.

Can anyone give me some advise ? Any helps are appreciated.
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Old   November 27, 2017, 06:32
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João Lourenço
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Quote:
Originally Posted by tomding0107 View Post
Hi all,

I have some problems with the testcase "rae2822". The original case is the case 6 of RAE2822 and it works well.

But when I am trying to study the case 9 by only modifying the mach number and the angle of attack (0.734 for Mach and 2.79 for angle of attack), the solution can be poorly convergent and not stable at all.

Can anyone give me some advise ? Any helps are appreciated.
I have the same problem too. Anyone can help?

Thanks,
Joao
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Old   November 27, 2017, 06:48
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I have the same problem too. Anyone can help?

Thanks,
Joao
You may change Reynolds Number, too. Also I suggest using Roe instead of JST. Are the y+ values below 1?
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Old   November 27, 2017, 07:59
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Originally Posted by whizkid View Post
You may change Reynolds Number, too. Also I suggest using Roe instead of JST. Are the y+ values below 1?
Hi,

According to AGARD paper, and other papers, the Reynolds Number is almost the some. In case 6, I'm using a mach number of 0.729 and an angle of attack of 2.31 and, for case 9, a mach of 0.734 and angle 2.79.

My y+ is 2.6 (above 1) and the turbulence model is Spalart-Allmaras. I attached my configure file.

thanks for the help.
Joao

Turb_SA_RAE2822.txt
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Old   November 27, 2017, 08:12
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Quote:
Originally Posted by JPBLourenco View Post
Hi,

According to AGARD paper, and other papers, the Reynolds Number is almost the some. In case 6, I'm using a mach number of 0.729 and an angle of attack of 2.31 and, for case 9, a mach of 0.734 and angle 2.79.

My y+ is 2.6 (above 1) and the turbulence model is Spalart-Allmaras. I attached my configure file.

thanks for the help.
Joao

Attachment 59800
If you can, I suggest generating a better mesh around the airfoil such that y+ values are below 1 on the surface. There is no wall function for SA in SU2.
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Old   November 27, 2017, 08:53
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If you can, I suggest generating a better mesh around the airfoil such that y+ values are below 1 on the surface. There is no wall function for SA in SU2.
Yes, I can and I'll do it. Can you explain me better why the value needs to be below 1?

Thanks
Joao
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Old   November 27, 2017, 12:38
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Yes, I can and I'll do it. Can you explain me better why the value needs to be below 1?

Thanks
Joao
here a discussion on the matter https://goo.gl/ESAKcK
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Old   November 27, 2017, 13:38
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here a discussion on the matter https://goo.gl/ESAKcK
Thanks for your help. I will check.

Joao
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Old   November 30, 2017, 10:48
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here a discussion on the matter https://goo.gl/ESAKcK
I have done your suggestion and the solution converges. Now I`m trying to do a shape optimization using continues adjoint but the adjoint solution doesn`t stop and take a long time. Can you help me?

Thank
Joao
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Old   November 30, 2017, 11:24
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I have done your suggestion and the solution converges. Now I`m trying to do a shape optimization using continues adjoint but the adjoint solution doesn`t stop and take a long time. Can you help me?

Thank
Joao
I suggest looking at some tutorials for that. I believe there are some airfoil optimization cases in the Test Cases repo.
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