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Hi Ramadas,
6250 = Failed to evaluate variable Jacobian.
This usually means that you have an unknown funcion or expression in some of your material parameters or boundary conditions. If you click "Show details" in the error message, there will usually be a clue to which expression was not recognized.

Niklas

Hi,Niklas,

Thanks for the clue. I checked the 'Show details'. It is in the attched file. It is not clear which is the problem function. Could you have a look at it

Regards
Ramadas

Hi

If you tell us a little more about what you are doing you will get a better help. Just by giving in wich application mode you operate is a good clue, therefore I suggest that we all should start our calls with a [V3.5a smsld] or whatever version and application mode(s) we use, and have this in the Subject field, it would then ease the sorting for later too.

Back to your issue, if you are playing with Navier Stockes, one error we often do is to have 2 dependent variables p & T, but we define clearly ony one (T) and forget about "p" the pressure. Often to set it at one place is enough to solve the system (but sometimes we give it also at two places with different values even if physics does not allow it, typos are so quickly done ;)

good luck
Ivar

Hi Ivar,

Thanks for reply. To tell more about the problem, I have attached the model file.It has 2 subdomins, 1 with convection and conduction , other with convection and diffussion. There is no parameter denoted with p. It shows error with p.


Thanking you once again

Ramadas

Hello everybody,


I'm new to Comsol. I want to simulate just a really simple system.

I took a 2D-Square filled with air, and a 2D-"Cylinder" with a teflon wall and filled with water. I used the general heat transfer modul.It works with water as 2D-Square-Material but not with air.
I get the same error message:
Error 6250, Failed to evaluate variabel Jacobian
- Variable: p
- Geometry: 1
- Subdomain: 1

When I take a look at the subdomain-setting, the density-line is showed in red. When I enter a numerical ratio, I get the same Error-Message. So I tried to build just a sqaure filled with air and I got the same problem.

I think it is a problem with gaseous materials, because I got the same problem with nitrogen.
Is it a problem with the materials library or simply with gaseous materials?


Thanks for your help.


Timo

Failed to evaluate variable jacobian
- Variable: u
- Geometry: 1
- Dimension: 2
- Domain group: {1}

What could this error mean? I use u only when i have to couple general HT with Weakly Compressible NS. Version is 3.4.

Did you figure out how to do it? If yes, please let me also know!