[Starcatcher]

Hi folks,
for a while now I am trying make a buoyantPimpleFoam-simulation work. The physics are simple. Water domain of 200x250x100m. There is an inlet and an outlet inside.
The temperature of the domain is 280K the temperature of the water coming in 190K.
The simulation diverges with the notification that the maximum number if iterations is reached. I don't know what i do wrong. Please help.

Here my boundary conditions:
Outer walls are all "empty" for all Fields. I also tried zerogradient and the standard


Inlet and outlet are zones which i created based on stl files with "createBaffles -overwrite"
T for inlet is fixedValue for all other fields zeroGradient.
U for inlet is flowRateInletVelocity for inlet, pressureInletOutletVelocity for outlet and slip/noslip/or empty for the outer walls
for p and p_rgh i tried different stuff, however here i am not sure. I think the standard is fixedFluxPressure for everything except of outlet. at the outlet i also tried prghPressure for p_rgh and $calculated for p.


This simulation should not be so instable, no idea, why this solver makes so mus issues.
I also noticed that it is much more stable if i defeine the density as constant. But this misses the purpose of the simulation. I want to simulate buoyancy.
idealGas also works, but i need water.
Also the instability grows with the level of paralelisation.


If you need I can provide more information
Thank you for your help.

[Starcatcher]

problem solved. among others the solution was to change the thermal energy equation setting from sensibleEnthalpy to sensibleInternalEnergy.
but why?