Reply To: Non conformal interface with unwanted Matching

[Lucjan Nastalek]

 

Rob, 

No, the mesh is not identical, the interfaces are non-conformal. 

– edit –

To summarize my adventure with using the different types of interfaces…

Switching on turbo models on, and then setting up general interfaces would enforce the “matching” option on all of them.

Not switching turbo models on, does not enforce it. 

Just a strange (perhaps intended?) behavior that I’ve noticed. I’d like to hear from the developer team if this is indeed intended.

I could, therefore, create the general interfaces with “mapped”+”coupled” options (but not “matching”) prior to turning on turbo models.

Turning turbo models after the creation of those general interfaces would not alter those settings (they would remain “mapped“+”coupled”  w/o “matching“).

– end of edit —

However, I’ve discovered that :

1. yes – the interfaces were partly causing the divergence issue.
2. no – the interfaces were not entirely responsible.
3. running the case, first with constant density of air allowed it to converge, albeit with wrong pressures
4. switching to ideal gas after 3. allowed me to converge the compressible case.
5. Because I am modeling a full 360° wheel geometry/mesh, I found it better to avoid using the turbo interfaces.
6. I think (in my opinion, not backed up by any research into it as yet), that the turbo interfaces do not “like” to be applied at an axial exhaust of a radial turbine – perhaps something to do with the radial distance of 0 at the centerline, and therefore some division by 0. 
7. general interfaces work like a charm, even with the MRF approach.

Would you be able to confirm or deny the limitations of the Mixing plane/ No Pitch Scale interfaces for radial machines? 

 

Thanks,

LN