Two-way coupling of Lagrangian particle

[lehongduc]

Hello all,

I would like to use two-way coupling of Lagrangian particle in Code_Saturne 4.0.3 but I have an unrealistic value of my results (about fluid velocity). I'm looking for some information about two way coupling of CS and I found a topic about it a year ago:

http://code-saturne.org/forum/viewtopic.php?f=2&t=1787.

And eventually, there has been no validation of two-way coupling yet.

My question is : are there any improvement or validation of two-way coupling since last year?

For my case calculation, it's quite confidential, I cannot upload it in the forum.

Thanks in advance.
Best regard,
LE Hong Duc

[Yvan Fournier]

Hello,

Actually we have one validation test case which does 2-way coupling, but only tests some combinations.

Are you using specific physics such as combustion, or just basic Lagrangian options ? Which turbulence model are you using ?

There have been some general improvements in version 4.3, but it has only undergone simple validation (the full validation will come this winter for an April release of 5.0).

Regards,

Yvan

[lehongduc]

Hello Yvan,

Thanks for the reply. I'm using only basic Lagrangian options. Turbulence model is "k-epsilon". The options of 2-way coupling is: nstits = 1, ltsdyn = 1.

I tested the integration order of SDE (nordre = 1 or 2), and also the activation or not the dispersion model (idistu = 0 or 1), those options doesn't fix my problem.

Could I have access to the validation test case of 2-way coupling that you mentionned?

Thanks in advance,
Best regard,
LE Hong Duc

[Yvan Fournier]

Hello,

For which version of the code would you need the validation test case ?

Regards,

Yvan

[lehongduc]

Hello Yvan,

I'm using CSv4.0.3. It would be nice if you have the validation test case of this version. If not, the validation of another version closest to v4.0.3 could be fine, I will try the same validation test case on v4.0.3.

Thanks in advance,
Best regard,
LE Hong Duc

[Yvan Fournier]

Hello,

Here is a case:

Regards,

Yvan

[lehongduc]

Re,

Thanks very much! I'll take a look at it.

Regard,
LE Hong Duc

[lehongduc]

Hello Yvan,

I found my "bug". I have to set first order of numerical scheme of particle dispersion model for 2-way coupling. (nordre = 1 in uslag1.f90). I didn't look closer to see what is the probleme with nordre = 2 (maybe some probleme in predvv.f90 for source terme (ligne 16510))... but my case works now.

Thanks again,
Best regards,
LE Hong Duc

[Yvan Fournier]

Hello,

Yes, when updating the algorithm for V5.0 (in progress), our Lagrangian expert detected an issue in the 2nd order terms. As the fix was quite intrusive, it was done only in V5.0 (current development trunk). We should force 1st order for future V4.0 bugfix releases to avoid this issue.

Best regards,

Yvan Fournier