[Carsvo]

Hello,

I have been using 2 versions of OpenFOAM. OpenFOAM v2006 and OpenFOAM v7.

The case I am running is a rotating disk and a stationary disk with a gap between each other. Furthermore I also model the ambient atmosphere around it to minimize the influence of boundary conditions.

I have checked the mesh with checkMesh and there is a bit of orthogonality/skewness, however it seemed to be okay.

when running the case with OpenFOAM v2006 and the buoyantBoussinesqSimpleFOAM solver a time step continuity error occured, since the value exploded to a very high number. This is quite odd, since when running the case with simpleFoam, this error does not occur. I thought this error was due to the mass conservation not conserved? I have also tried to use the compressible solver buoyantSimpleFOAM, however this also didn't work since the temperature became negative and the density diverged to unphysical values.

When I use OpenFOAM v7, (which uses the buoyantSimpleFOAM, with a boussinesq assumption) , it does not give this error and I can run the case for more iterations without any problem.

Does anybody know why this is the case? is the solver in v2006 not correct or does it handle certain cases worse? ( since I am not too confident in my case now)

If I need to provide more information, let me know!

Kind regards,

Cars

[dlahaye]

Does your case convergence by limiting T and/or U?

limit temperature (https://www.openfoam.com/documentati...mperature.html), (especially this on) and velocity (https://www.openfoam.com/documentati...-velocity.html) using settings in fvOptions dictionary;

[Carsvo]

Hey!

thank you for your answer. I do not fully understand how limiting the temperature would help. I have read it is for when the solver cannot capture the temperature in the first iterations. Is it meant to be turned of after the solution gets more stable?