Hi Bruno, thanks !

Thanks for the threads link, i'll read them carfully, but i think my problem is more basic than that...


I ran the kivatest tutorial case both with engineFoam from OF1.7.1 and OF 2.1.1 (each solver with the appropriate version of the case, of course...).

In OF1.7.1, the case work just fine, but in OF 2.1.1, temperature and pressure do not increase, wich is... wierd for a compression. Worst than that, in some aera of the domain, temperature drop to 200K and lower...

I've checked the boundary conditions, and even every file in the kivatest 2.1.1, and it's the same as the kivatest 1.7.1 (except for some syntax), so my humble guess is that the problem comes from the solver or from one of the parameter like the maxCo, number of correctors, time step, ...

What's wierd is that i haven't made any modification to the tutorial case so... it should work... or am i missing something?


I've read here (http://sourceforge.net/apps/mantisbt...view.php?id=46 , link from the thread you've posted) that a year and a half ago, the same bug was observed in 1.6... But if it works correctly in 1.7, one can assume that the problem has been resolved... My question is how? :-)
Let's hope the same method can be used to fix engineFoam 2.1.1 ...

Thanks again !


Gregory

Hi Gregory,

OK, then more information is going to be necessary for trying to isolate the problem:

• What Linux Distribution are you using and version?
• 32 or 64bit?
• How did you install OpenFOAM? From Deb/RPM or from source?

If this was witnessed in the past, it might be a corner case, where an alignment of characteristics leads to things not working as intended.

I didn't have time to do a full run on this tutorial. But in 24-48h I might be able to look better into this. Therefore knowing more about the installation you're using, might help isolate the issue.

Best regards,
Bruno

I have ubuntu 12.04 lts, 64 bit. And I used the Deb pack for the install.

We tried it on different computer, and the problem remains the same :
on a 32 bit ubuntu 12.04, OF2.1.1 deb pack install,
on a 64 bit ubuntu 12.04, OF 2.1.0 source install,
on a 64 bit CenTOS, OF 2.1.0 source install ...


Since pressure increase to 7.6bar at -15 CAD, (it is supposed to be around 14bar) and the temperature drops below 200K in some aera of the domain, i've checked the boundary condition in the -180 folder and they are the same.
I also double checked every coefficient in thermophysicalProperties, and they're the same... If it isn't caused by the type of OS or install, maybe something with the ideal/perfect gas law ? (wild guess...)

I tired changing the T file in -180, using higher & lower initial temperature, i tried changing the boundaryfield type from fixed value to zeroGradient (to have adiabatic walls), but it doesn't change anything.

Thanks for the help Bruno, really appreciate!

Gregory

Hi Gregory,

OK, after testing this case on my machine with Ubuntu 11.10 with a more recent version of OpenFOAM 2.1.x, I've come to the conclusion that this case falls into the same category of this bug report: http://www.openfoam.org/mantisbt/view.php?id=571

As you can see from the last comment, the next release of OpenFOAM (hopefully) should have this issue fixed properly, since it falls into the same category of issues with thermodynamics that OpenFOAM has.

I believe that since OpenFOAM 1.7.1 works with this tutorial, then 2.0.1 should be working as well, or at least 2.0.0. The modification made to the code for trying to make models for thermodynamics more realistic was made somewhere in 2.0.x, as indicated in one of the links I've written about the other day.

So basically, you can still use 2.1.1 for everything not thermodynamics and 2.0.1 or older for the ones you do need thermodynamics.
edit: A reminder that this was modified in 2.0.x due to this bug report: http://www.openfoam.org/mantisbt/view.php?id=346

Last but not least, I think they (the OpenFOAM team) always welcome sponsors for improving parts of the code, such as this! ;)

Best regards,
Bruno

Okay, i'll try 2.0.1 and i'll post a feedback !

Last quick question : I'm not really sure of what you mean by "everything not thermodynamics", is this suppose to include every solver that use "thermophysicalProperties" ?
Because for example, i've ran every tutorial case for combustions with OF2.1.1, and they're working fine. Don't they "use" thermodynamics? For example, in engineFoam, isn't the combustion part based on the XiFoam solver?
I use reactingFoam with other cases than the tutorial and results are good, so..

I've run the sprayFoam tutorial (aachenbomb) and it seems okay, and then i've transformed the kivatest tutorial to use sprayEngineFoam, and Temperature is dropping, like in engineFoam. (i'm not even talking about problem with the spray, i was just checking if the compression phase of the engine works...)

I don't know if this is of any use, but could it be caused by the moving mesh? Is there another tutorial case with moving mesh with or without thermodynamics that I could test?

One last thing that i've noticed : If you use the kivatest case, but starting from top dead center so that the piston head go down (decompression), there is a tiny zone juste above the piston surface where temperature increase (373K->500K). I'm aware that it could be caused by the bad formulation of internal energy in specieThermoI.H, but the fact that temperature drops everywhere else (as it should) except for that aera near the moving piston head make me wonder...

(Then again, the aera near the moving piston head is the aera where the speed magnitude is maximum, so it could be a problem with the kinetic energy witch is part of internal energy... and we're back at the starting point.)


Sorry if my post doesn't make much sense, i hope i wasn't just thinking out loud and some of this will actually be of use !

Thanks a million, Bruno !

Gregory

Hi Gregory,

Well, the italic not was implying a somewhat generic idea that whenever things don't work on 2.1.1, try using the older 2.0.1 ;) I should have been more clearer about what I really meant :(

As for your doubt about the moving/dynamic mesh - feel free to report this on the bug tracker: http://www.openfoam.org/mantisbt/
It might take a while for them to answer back though. And give the same level of details you've given here about this issue with the dynamic mesh and this tutorial case.
Keep in mind that simply giving a link to this thread won't be enough, since there is a lot of info to go through here :(

With any luck, the dynamic mesh issue might be something that they can back-port from the ongoing development of the next release of OpenFOAM.

Best regards,
Bruno

Hi Bruno,

engineFoam tutorial with OF2.0.1 is working just fine (wich is a great relief ;-) )

I'll dig more about the dynamic mesh before posting anything on bt, i don't wanna cry wolf !

Is there a due date for the next release? (or at least for a correction of internal energy behaviour)
Because if it is corrected, and engineFoam still isn't working, then maybe more experienced people will check an hypothetical dynamic mesh problem... (I can try but i'm a beginner in OF :) )

I hope I didn't take to much of your time,

Regards,
Gregory

Hi Gregory,

I don't think there is any publicly official date for the next release, so there are only guesses.
One such guess is that it might be only released in December, one year after 2.1.0 was released.
Another guess would be to celebrate the Foundation's 1st year, this August.

Best regards,
Bruno

Hi Paladin, I've your same problem with kivaTest in OpenFoam 2.1.1 and so I want to know how you have resolved it. Did you have downloaded version 2.0.1 or according to you should I use the latest version 2.2 ?
Thanks a lot,
Vito

Problem solved
 

The problem was a bug of OpenFoam 2.1.1 ; with the latest version (2.2.1) engineFoam works fine