Thank you for comment, Glenn.



The upstream domain is periodic, therefore I model just a segment. Flow transfer between 60deg segment to 360deg domain can be done only by MRF or not? Is there another way to include a segment and to "copy" the velocity field to full 360deg domain?

You are talking about one big stationary domain without segment (zou assume 360deg to 360deg glued mesh - one domain) but I need 60deg to 360deg to reduce mesh elements.

You are not doing a MRF simulation, as everything is in the stationary frame of reference. That is a single frame of reference, not multiple.

But if you want to model only a 60 degree segment and have it mapped to a whole 360 ring then I think you need to do what you have done. (But it is not MRF, it is just using the GGI and periodicity to copy the 60 degree segment around).

Sorry for wrong term, yeah it is not MRF in fact. There is no easy way out. When using periodicity, gravity does not work. Setting gravity to selected domain only would help, it could be topic for CFX developers.

I think they will just recommend you to buy a larger computer and a full commercial license.

Can't you model the 60° segment alone, then export a boundary profile on the interface and use that in a separate simulation on the complete circumference with gravity? You only need to copy the profile 5 times to reposition it over the complete 360-interface.

Exactly. And they will release a new version with new ribbon.




This is exactly what I am gonna do - my comment from 11.1. 15:51.


Thank you all for discussion!

You can set gravity for a single domain (disable constant physics in the beta features), but you will be on your own.

Recall that pressure is shared across the interface; therefore, it is a tricky situation having different definitions of pressure on both sides, is it not?

Thank you for sharing this possibility. I tried it but it does not work. The computation crashes in the same way as when gravity is switched on in both domains (the same behaviour as shown in the output file I uploaded some days ago.