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-   -   OF ESI and OF org giving different results (https://www.cfd-online.com/Forums/openfoam/244113-esi-org-giving-different-results.html)

twnspl July 22, 2022 05:09

OF ESI and OF org giving different results
 
I recently shifted from OF from ESI to OF from openfoam.org and I ran one of my old wing simulation cases I found that the forces from that wing are orders of magnitude higher that what I had obtained from the ESI version. I was getting about 200N for the ESI version but I am now getting 1.4e6 N which is physically not possible. I have not changed anything in my case file. As far as I know both versions are not that different from each other is there something I am missing ?

Yann July 22, 2022 05:30

Hi,

It would be interesting to know which version you used on your reference case and which ESI and foundation versions you are using now.
ESI and foundation branches are slowly diverging from each others, with major changes on many aspects.

On your case, I would start by checking other quantities such as pressure and velocity fields to see if the difference lies in the force calculation or if there is something going on with the flow itself.

Yann

twnspl July 22, 2022 05:51

Quote:

Originally Posted by Yann (Post 832237)
Hi,

It would be interesting to know which version you used on your reference case and which ESI and foundation versions you are using now.
ESI and foundation branches are slowly diverging from each others, with major changes on many aspects.

On your case, I would start by checking other quantities such as pressure and velocity fields to see if the difference lies in the force calculation or if there is something going on with the flow itself.

Yann


I used OF v2106 for the initial cases and now I am using OpenFOAM 9. I am trying to run the case in my friends workstation which has ESI v2206 to check.



I did not know that both versions were becoming different, that something I learnt today. Thanks !

Yann July 22, 2022 06:00

To be honest I am already surprised you could run your case from OpenFOAM-v2106 on OpenFOAM-9 without changing anything in the case setup!

Let us know how your tests go!

Yann

twnspl July 23, 2022 00:28

Quote:

Originally Posted by Yann (Post 832241)
To be honest I am already surprised you could run your case from OpenFOAM-v2106 on OpenFOAM-9 without changing anything in the case setup!

Let us know how your tests go!

Yann


ESI v2206 gives the same result as the v2106 so I presume that the .org version doesn't like the ESI one. I think I have to switch to ESI version.

Yann July 25, 2022 03:49

Thanks for your feedback!
If you want to stick to the .org version, you may want to investigate on where the result difference lies. Is it only on the force calculation (it may be as simple as fixing the function object setup) or do you get a different flow?

Regards,
Yann


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