code_saturne User's Forum

Hi !

I have successfully reduced the amount of instabilities by using "local time stepping" and increasing the reference time step.

This is very unusual to me: in my referential increasing the time step means amplifying the numerical instabilities. Is the time stepping explicit or implicit ...

Thank you Yvan for your fast answer and sorry for the missing attachement. I remember adding it to the post, but I certainly did not go all through.
Here is the screenshot at iteration 700, we can see the plume which has formed at the left heating bar (others have been deactivated), and the ...

Hello,
I am running a code_saturne simulation where 3 heating bars are embedded within a still air environnement. The only dynamics of the case is elevating air due to buoyancy at the heating bars.
For the Boundary Conditions, I have imposed a wall at the bottom and I wish to let the three (left ...

Here are the thermal Flux and Boundary_temperature at boundaries.

1. Why are these quantities given on the volumic mesh and not only at the boundary faces?
2. The input thermal flux is globally negative. Does it mean the heat is going from the fluid to the solid?
3. The heat exchange is not ...

Hello,

I am quite confused by the coupled Syrthes/Saturne result I get. I have a heating solid bar centered within a fluid domain. The solid bar is heated by Joule effect which I temporarily model by a handmade heating field.

What I am interested in is the thermal transfer between the solid bar ...

All right! I have been able to run the simulation by rearranging the <conjugate_heat_transfer> as:

<conjugate_heat_transfer>
<external_coupling>
<projection_axis>Z</projection_axis>
<syrthes_instances>
<instance name="SOLID">
<coupled_boundary label="Barre1_P1"/>
</instance>
</syrthes ...

Hi Yvan,
Thank you for your answer.
In my setup.xml Saturne's config file, I have the following section :

<conjugate_heat_transfer>
<external_coupling>
<syrthes>
<projection_axis>Z</projection_axis>
<selection_criteria>1</selection_criteria>
<syrthes_name>SYRTHES</syrthes_name>
<verbosity ...

Hi,
Now that I have been successfully able to run the Syrthes' coupling tutorial 3_DISKS, I have tried to report the procedure to my own test case. Both simulation (Syrthes and Saturne) work independently.
However, once I try to run the coupled simulation, the Syrthes process crashes with the ...

Thanks Yvan, that was exactly the problem !

Maybe all this should be added to the 3_2D_DISKS step-by-step document in a prerequisite sub-section of the introduction :

### Prerequisite

* Saturne 8.0.x compiled with mpi support :
```bash
/configure –prefix=path/to/install/dir --with-mpi ...

Hi Yvan,

Thank you very much for your quick answer!

I have been looking at the compilation logs of Saturne and Syrthes and both seem to use /usr/bin/mpicc for the mpi part.

Then I noticed that Syrthes compiles two separate libraries : the 'seq' and the 'mpi' one. I suddenly remembered that ...