[CellZone]

Hi,

I am looking at the source code of potential foam:

1. when I open createFields.H of potential foam it says:

"surfaceScalarField phi"

What does this stand for? And how can I imagine this?

2. then it is said
fvc::interpolate(U) & mesh.Sf()

What does this mean? Phi is interpolated of U and?

3. For volVectorFields it is normaly replaced by "mesh" . What does this mean?

I allready read wiki etc. but I don't get it. It's hard to find a documentation about it.

Thank you

[Bloerb]

phi is the flux. The flux is for compressible solvers rho*u*A or otherwise u*A on the faces. Or more precisely the flux between cells. Your velocity field u in your timestep folders is saved at the center of each cell. The flux on the other hand is the value on the faces between cells. It is the flow from one cell to the next. Therefore it is a surfaceScalarField and not a volScalarField like u. You can calculate your flux with different methods (upwind linear etc).

now to your method here:

fvc::interpolate(U) & mesh.Sf()

fvc:: is finite volume calculus and is used for calculations on those fields. fvm on the other hand is used for equation systems. So interpolate(U) gives you the velocity on the patch. mesh.Sf is the surface vector (area and normal of the face) and & is the scalar product. Hence the scalar product of u and the surface vector gives you the flux. While u is m/s your 0/phi file tells you the flux is m^3/s.