Additional Variables at the Opening Boundary

Houman

Hi everyone,

I am modeling a multiphase system, in which I need to introduce two Additional Varialbes (AV) for each phase (water & Air) which they would be considered as oxygen concentration in each phase...

Problem: I have an opening boundary condition at the top of my model at which, the water is freely going in/out, (of course the same water in the domain). this means that I need to be able to set the (AV)s at the OPENING condition in a way that no new water comes in (but the same water contating the specitic oxygen concentration shall only enter the domain...)

FYI, I'm using transient settings

Would highly appreciate any help/comments...

Houman

PS: in some of previuous messages I came across this;

BOUNDARY: out

Boundary Type = OPENING

Location = out

BOUNDARY CONDITIONS:

MASS AND MOMENTUM:

Option = Extrapolation

END

END

END which is interesting, but I couldn't use it without error message!!! and also in this case I don't know what happens to the AVs?