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-   -   Differents results between OPF2.1.2 and OPF2.30 (https://www.cfd-online.com/Forums/openfoam-bugs/150120-differents-results-between-opf2-1-2-opf2-30-a.html)

ynos March 16, 2015 05:29

Differents results between OPF2.1.2 and OPF2.30
 
Hi Foamers
I have got differents results when I run the same model with OP211 and OP230, the only one file that I change is fvSchemes.

OPF211
divSchemes
{
default none;
div(phi,U) Gauss linearUpwindV grad(U);
div(phi,k) Gauss upwind;
div(phi,omega) Gauss upwind;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}

OPF230
divSchemes
{
default none;
div(phi,U) bounded Gauss linearUpwindV grad(U);
div(phi,k) bounded Gauss upwind;
div(phi,omega) bounded Gauss upwind;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}

Can anyone help me?
Thanks in advanced

alexeym March 16, 2015 05:58

Hi,

If you really like to get an answer it is better not to increase the number of posts with the same content but

1. Provide more detail on your case (from "bounded" keyword addition I can conclude that you are using steady state solver, but that is all I know about your case and it is not enough).

2. Explain real meaning of "I have got differents results".

ynos March 16, 2015 06:35

Hi there
I meshed a geometry with OPF2.3.0. And then run this mesh with OPF2.1.1 and 2.3.0. Everyfiles are the same except the fvSchemes, you can see the diferences down.
I get different results in the integration of forces ,on the order of 10%


OPF211
divSchemes
{
default none;
div(phi,U) Gauss linearUpwindV grad(U);
div(phi,k) Gauss upwind;
div(phi,omega) Gauss upwind;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}

OPF230
divSchemes
{
default none;
div(phi,U) bounded Gauss linearUpwindV grad(U);
div(phi,k) bounded Gauss upwind;
div(phi,omega) bounded Gauss upwind;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}

Can anyone help me?
Thanks in advanced

pablodecastillo March 16, 2015 15:06

I did the same test with streambody , with 0 angle of atack and i got 7.3 % diference in pressure drag between 2.1.1 and 2.3.1 versions. Same Mesh, same fvsolution , fvschemes .... just adding bounded in 2.3.1 for divSchemes.

Coments are welcome.

Phicau March 17, 2015 06:06

I guess Henry Weller pointed out this "not-an-issue" thing in my bug report that you can find here:

http://www.cfd-online.com/Forums/ope...-versions.html

pablodecastillo March 17, 2015 08:00

Following the code linearUpwindV.C, has changes between 2.1.x and 2.3.x, i will back to the old version and recompile, i will inform if it is improving.

pablodecastillo March 18, 2015 14:47

Still similar diferences, lastest times i meshed with 2.3.x and run with 2.1.1. I decided to move run to the 2.3.x also, but results are too diferents.

Really, i can not understand if other user and developers never got same problems.

At the end editing linearupwindV.C and coment lines from 137 to 216 (both included), i got really similar results. Of course you must recompile the obj.


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