I want to define a thin surface inside a flow domain, where I want to set some user scalar boundary condition (potential), but the other mass fractions should walk through all the flow domain which is porous media. The runsolove did not converged when I write "porous wall" in >>wall boundary conditions. If I comment this, it is converged, but that is not my situation.

The CFX support person are in holiday, that is a pity, but it is urgent for me to work it out soon. Any one have some advice for this?

Thx.

There are no "porous wall" conditions. Sorry. Assuming you're working on something fuel cell-esque, this is a very hard boundary condition to implement. Perhaps making the first layer of cells very thin and applying a "volumetric" source equivalent to what the "area" source would be for a wall? That's my best suggestion.

Jeff

Not 100% sure I understand, but if you prescribe a source on the one side of the thin surface in the adjacent cells (which you define as being very thin), then you may also have to define a sink on the other side of the thin surface ? I'm not sure if you can define a variable source/sink that is dependent upon the volume fraction of scalar that is upstream of the thinsurface ?? if that is what is indeed needed ? Bob