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-   -   General help for fvSchemes and fvSolution settings (http://www.cfd-online.com/Forums/openfoam-solving/57859-general-help-fvschemes-fvsolution-settings.html)

harly March 3, 2009 20:16

Hi, I am playing around wit
 
Hi,

I am playing around with OpenFoam for quite a while now but I still have my problems when it comes to choosing the "order" and "schemes" for those files.

In general I understand what every entry does and what the influence should be - but lately I ran in trouble with a perfectly working set of files and I could not figure out why.

My question would be if you have any general tips you can give me or even just paste a fvSchemes file you are using.

Right know I try to get a very good result for the drag of a sphere in low Re number area (50 - 200) so far I am using IcoFoam, but I am open for any suggestion to improve my current results.

My current fvSchemes:
http://harly.de.vu/www/sphere/fvSchemes
My current fvSolutions:
http://harly.de.vu/www/sphere/fvSolution

These files worked great for me for Re=200 and Re=150, but on the same mesh and lower Re (50,100) the Drag is too high.

Thanks a lot
- harly

santos March 4, 2009 10:41

Hi Daniel, I would use back
 
Hi Daniel,

I would use backward or CrankNicholson for ddt, limitedLinearV for convection, and I would tighten the tolerance a little both on p and U.

Regards,
Jose Santos

harly March 4, 2009 15:02

Thanks for the input I will ru
 
Thanks for the input I will run a simulation with these settings and will report back - other comments are very welcome.

- harly

harly March 4, 2009 15:26

So, I am running now with t
 
So,

I am running now with the following modifications:

ddtSchemes
{
default CrankNicholson 0.5;
}

divSchemes
{
default none;
div(phi,U) Gauss limitedLinearV 1.0 phi;
}

p PCG
{
preconditioner DIC;
tolerance 1e-07;
relTol 0;
};

U PBiCG
{
preconditioner DILU;
tolerance 1e-06;
relTol 0;
};

I will report back when I have some results.

zebu83 September 7, 2009 11:31

Hi Daniel,
did you have a better results with the new settings?

Thank you
MT


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