Problem at interface: an object is present but it is not physically valid
 

Hello dears,
I'm doing a simulation with a part made of a porous domain with a solid phase and a fluid phase (resin), with an additional variable defined only inside the resin ("alfa", additional variable defined through a transport equation). The porous domain flows in a steel die: with this configuration all works fine.

When I insert in the porous domain also a second fluid (air ideal gas),
I have a warning that say me:
"The object "ADDITIONAL VARIABLE: alfa" is present in the object "/FLOW:Flow Analysis 1/DOMAIN:Part/BOUNDARY: Default Solid Porous Interface Side 1/BOUNDARY CONDITIONS" but it is not physically valid.

Substantially I have a problem at the die-part interface (at porous domain side).
Opening the specified interface window, it isn't possible to delete alfa from the interface.

How I can do?

Hello, anyone can help me?
Thanks

I am not sure but I suspect you have to define your AV in all domains. I do not think it can only exist in one domain.

Hello ghorrocks, if I set the simulation with only resin as fluid component of the porous domain and I define the additional variable only in the porous domain (not in the solid (die) domain) all works fine.
So I don't think it is a problem of domains, I think that could be a multiphase problem, because it only presents when I introduce the air...

Any other suggestion, boys?