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Periodic flow using Cyclic - comparison with Fluent |
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October 21, 2015, 08:14 |
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#21 |
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Philipp
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For the mapped case:
You set the velocity to some fixed value at the outlet. Of course you will not get the same as in cyclic. Also the pressure boundary condition is wrong. So you should really try to use the boundary conditions for mapped case that I used in my old thread. Why did you change them?
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October 31, 2015, 11:04 |
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#22 |
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Hi,
It has been quite a mad week, so I struggled to reply. I tried implementing conditions your suggested and I did not achieve much success for Re=200 case, which should be low. It struggled with the covergence as shown below: RESIDUALS.png The case files are again in dropbox: https://www.dropbox.com/s/sjd6e552fb...mapped.7z?dl=0 |
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November 2, 2015, 02:22 |
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#23 |
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Philipp
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The files you uploaded converge on my computer.
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November 2, 2015, 05:28 |
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#24 |
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Hi,
That did slightly confuse me. What version are you using of OpenFOAM? I have just downloaded the files myself and got the same behaviour as in the post on Saturday. |
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November 2, 2015, 05:30 |
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#25 |
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Philipp
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It says "2.3.x.".
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November 2, 2015, 14:27 |
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#26 |
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That is fairly weird - I did load 2.3.1 (normally using 2.4.0) and I still got the same result
Do you have any of the solvers modified? Could send back the file? I would be interested to see it. |
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November 2, 2015, 14:54 |
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#27 |
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Philipp
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The skeleton ran out of shampoo in the shower. Last edited by RodriguezFatz; November 3, 2015 at 03:10. |
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November 3, 2015, 05:28 |
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#28 |
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I have just now done exactly the same and got a following:
Screenshot-1.png This is really getting weird and hardly explanable |
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November 3, 2015, 05:38 |
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#29 |
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Philipp
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These (1st. order) settings converge much smoother than yours:
Code:
gradSchemes { default Gauss linear; //grad(U) cellLimited Gauss linear 1; } divSchemes { default none; div(phi,U) bounded Gauss upwind; //linearUpwindV grad(U); div(phi,k) bounded Gauss upwind; div(phi,omega) bounded Gauss upwind; div((nuEff*dev(T(grad(U))))) Gauss linear; } laplacianSchemes { default Gauss linear uncorrected; }
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November 3, 2015, 06:33 |
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#30 |
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Hi,
Thanks for giving a bit of advice on the which schemes to use - I am still slightly confused how to set/modify these. It did converge. The result seems a bit different, but again, I need to evaluate some physical quantities. The documentation on them is slightly interesting sometimes. |
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December 12, 2017, 06:35 |
constant average velocity at inlet with periodic boundary conditions
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#31 |
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Qihao Jiang
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[QUOTE=nusivares;569006]Hello all,
As of OpenFOAM I imported the fluent mesh, created cyclic boundary conditions and used the fvOptions file to set the momentum source terms using mean velocity to make the things flow. I was simulating a channel flow which inlet and out are cyclic boundary conditions, while I do not know how to give a flow velocity boundary condition at the inlet to let it flow, can you add a flow velocity or discharge at the base of cyclic boundary condition? |
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fluent, openfoam, periodic flow |
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