[BigBoBy]

I have made a steady state simulation (in ansys fluent) of a Rayleigh benard convection "RBC" (rectangular cell heated from below and cooled from above).

I have the problem that the residuals and also other values like the average temperature and heat flux fluctuate. I have also changed the mesh and the relaxation values. But that did not make it any better.

My question is: The RBC is a thermally unstable system. Can this be the reason why the values and residuals do not become constant or converge? Or do I have to continue adjusting my boundary conditions?