[nandiganavishal]

Dear Foamers,

I was trying to characterize the dynamics of my system. I was solving the system using implicit (Backward Euler) method with very small time step. I found that the solution reaches a steady state at a finite time (say T). However, I observed small numerical fluctuations with error (of about 0.4% about the mean before it reached a steady state). I would like to know if it is possible to control this numerical error. I had tried reducing the time step and also played with the solver tolerance value, but could not reduce this small numerical fluctuation. Please let me know your suggestions.

Attached is the plot of the solution.

Thanks

[kilroy]

Hello Vishal,

Your fluctuations doesn't look so large. I don't know your case so I am not sure but this maybe because of something numerical. My advice for you is taking the average of your output after your system reaches steady state.

Hope this helps,

Kilroy

[nandiganavishal]

Originally Posted by kilroy

Hello Vishal,

Your fluctuations doesn't look so large. I don't know your case so I am not sure but this maybe because of something numerical. My advice for you is taking the average of your output after your system reaches steady state.

Hope this helps,

Kilroy

Thanks, Kilroy. Yes, I figured out that they were indeed numerical fluctuations about the tolerance level specified by me.

I would like to know if you have experience with SnappyHexMesh tool in OpenFOAM. I have couple of queries on this. Please let me know.

Thanks

Regards
Vishal

[nimasam]

dear Vishal
Open new thread for SnappyHexMesh tool, then OpenFOAM users will help you there

[nandiganavishal]

Originally Posted by nimasam

dear Vishal
Open new thread for SnappyHexMesh tool, then OpenFOAM users will help you there

Dear Nima,

Thanks for your reply. I have posted the question as a new thread. Below is the link for the same.

http://www.cfd-online.com/Forums/ope...tml#post434559

Please let me know if you can provide some help.

Thanks

Regards
Vishal