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Periodic flow using Cyclic - comparison with Fluent

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Old   October 21, 2015, 08:14
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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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Old   October 31, 2015, 11:04
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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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Old   November 2, 2015, 02:22
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The files you uploaded converge on my computer.
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Old   November 2, 2015, 05:28
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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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Old   November 2, 2015, 05:30
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It says "2.3.x.".
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Old   November 2, 2015, 14:27
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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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Old   November 2, 2015, 14:54
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I deleted the 1000, 2000, ... directories and typed "simplefoam > log". What did you do?

res.png
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Old   November 3, 2015, 05:28
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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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Old   November 3, 2015, 05:38
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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;
}
res.png
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Old   November 3, 2015, 06:33
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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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Old   December 12, 2017, 06:35
Default constant average velocity at inlet with periodic boundary conditions
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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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