Hello again. Thinking about
 

Hello again.

Thinking about the maxCo entry in controlDict I'm asking myself what this entry is good for if I'm using Euler implicit discretisation for the temporal derivative, which should be unconditionally stable for ALL timesteps.

What is maxCo limiting in this case?
The velocity field?

Greetings.

Hi Sebastian, yes, maxCo is
 

Hi Sebastian,

yes, maxCo is based on the velocity field. The stability is limited by the PISO algorithm, which is stable for Co up to 1 i think. But Co should be lower for interFoam, it should be around 0.25. To overcome this, you can use subtimestepping for MULES. A good choice is maxCo = 0.5 and two subtimesteps for gamma.

Concerning Euler: even if Euler is unconditionally stable, this does NOT mean that it is unconditionally accurate ;-)

Best regards
Christian

Thank you, Christian. That mak
 

Thank you, Christian. That makes sense.
Who can tell the correct Co-limit for PISO?