[Rovs]

Hello!

I'm trying to do a simulation with rhoCentralFoam.
During simulation delta T change from the delta T imposed in controDict file.
i imposed DeltaT=0.02 during simulation it become around 10^-7

How is it possibile?

[arsalan.dryi]

Hi Federico,

Check for adjustableTimeStep option in your controlDict, then follow this section of user guide, finally feel free to ask if any question exist.

Regards,
Arsalan.

[Rovs]

Originally Posted by arsalan.dryi

Hi Federico,

Check for adjustableTimeStep option in your controlDict, then follow this section of user guide, finally feel free to ask if any question exist.

Regards,
Arsalan.

Thanks you very much. I didn't see it. Now i have problem with courant number of course, probably i have to do a mesh with bigger elements.

[Rovs]

[CODE#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 in "/lib/x86_64-linux-gnu/libc.so.6"
#3 Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) at ??:?
#4 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::sqrt<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::fvPatchField, Foam::volMesh> > const&) at ??:?
#5
at ??:?
#6 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#7
at ??:?
floating point error
][/CODE]

Now i have this problem, but i can't read where is the problem.

[rhythm]

Hi,

The error message on it's own doesn't really help, so uploading your code might help users around here to help you more.

Anyway, Floating point exceptions usually come up when division by zero pops up in the code, or some mathematical operation is applied on a not a number (NaN) value.
Your error message is rather cryptic, but there is one thing that I notice:

#3 Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) at ??:?
#4 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::sqrt<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::fvPatchField, Foam::volMesh> > const&) at ??:?

We can notice the part Foam::sqrt<, which might be a clue as to where exactly the code is failing. So my advice would be to check whereabouts in your code a quadratic root function is called and see if the fields, that it should be applied on, are correct.

Hope this helps.
Cheers,
Ben

[Rovs]

Originally Posted by rhythm

Hi,

The error message on it's own doesn't really help, so uploading your code might help users around here to help you more.

Anyway, Floating point exceptions usually come up when division by zero pops up in the code, or some mathematical operation is applied on a not a number (NaN) value.
Your error message is rather cryptic, but there is one thing that I notice:

#3 Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) at ??:?
#4 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::sqrt<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::fvPatchField, Foam::volMesh> > const&) at ??:?

We can notice the part Foam::sqrt<, which might be a clue as to where exactly the code is failing. So my advice would be to check whereabouts in your code a quadratic root function is called and see if the fields, that it should be applied on, are correct.

Hope this helps.
Cheers,
Ben

Hello Ben, Thanks for reply.

I really don't know what can be squared. The solver is RhoCentralFoam.
What do you mean with upoload the code? all directory 0, system and constant? or just some file like u,p,T ?

[rhythm]

Hi,

I have guessed that you are using your own modified version of the solver, hence my suggestion. If you are using stock RhoCentralFoam, then I will take a look at what it does later today.


Anyways, are you running on a tutorial case or your own case?
If your own, then are you able to replicate the error message on one of the tutorial cases?

Finally, if you haven't fiddled with solver code, then my best guess is that your case setup has an issue somewhere (most probably in your boundary/initial conditions). So I would check them against a working tutorial case side by side and see what BC's they are using there and maybe this will give you a hint on where the mistake is present.

Cheers,
Ben

[Rovs]

Originally Posted by rhythm

Hi,

I have guessed that you are using your own modified version of the solver, hence my suggestion. If you are using stock RhoCentralFoam, then I will take a look at what it does later today.


Anyways, are you running on a tutorial case or your own case?
If your own, then are you able to replicate the error message on one of the tutorial cases?

Finally, if you haven't fiddled with solver code, then my best guess is that your case setup has an issue somewhere (most probably in your boundary/initial conditions). So I would check them against a working tutorial case side by side and see what BC's they are using there and maybe this will give you a hint on where the mistake is present.

Cheers,
Ben

I'm running my own case. An airfoil 2D, pretty simple.
I haven't touched the solver code.
The courant number is high. I've tried different mesh, but the problem still stand.