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Spalart Allmaras DDES - circular cylinder

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Old   February 24, 2013, 09:43
Default Spalart Allmaras DDES - circular cylinder
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edoardo
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Dear OpenFOAM users,
I want to make some aeroacoustical simulations coupling OpenFOAM with an opensource acoustic simulation code.
I am trying to simulate the von-karman vortex street after a circular cylinder at Re=166000. After performing 2D incompressible simulation with pimpleFoam solver and a k-omega SST turbulence model (getting quite good results in term of force Coefficients and Strouhal number), I would like to improve my simulation using the Spalart Allmaras DDES hybrid turbulence model. I made few tests (2D case), but I'm getting a non-physical behaviour (look at the animation). I also attached the case-study folder.
I would be very pleased to you if you could get me some suggestions.
Thank you very much!

1)DDES case-study: https://mega.co.nz/#!osgCHZYB!Vf4Yxg...TxQfzgX-sgWeGw
2)DDES animation (U magnitude):
https://mega.co.nz/#!JlxVQCCI!E0xGLS...cUx-AD5TmCu-1o
3) komegaSST case-study:
https://mega.co.nz/#!JgYDwSob!T9EYAl...5bG53ncqcMSWcA
4)komegaSST animation:
https://mega.co.nz/#!dkZmmIwB!KVs80U...TtuPfh6eXrYZnQ

PS: Sorry , I moved this thread which was previously posted in the wrong section, thanks!
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Old   April 9, 2013, 08:19
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Kai Zhang
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the website you posted does not work. Your cases can not be downloaded!
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Old   April 9, 2013, 09:25
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Hello!
I've just checked the links and they work! Can you please specify what kind of problem the browser gives you?
Thanks!
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Old   April 9, 2013, 09:38
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Ilya
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For my browser it needs to set up Flash.

But i have one question about your case. Did you use empty BC with one cell thick domain both in SST and DES case?
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Old   April 10, 2013, 09:40
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I think that you can't use DDES in a 2D simulation. DDES is a hybrid RANS-LES method in which you should capture the large 3D eddies in the wake. In a 2D simulation you are going to miss the effect of the vortex stretching that is important in the energy cascade process.
Probably this is the explanation for the non-physical results that you got.
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