[Wien3]

Good Morning,
I'm studying an OF model which consists on a cube which has a sphere inside. A fluid flows from inlet to outlet.
As it is incompressible, I think I have to assign the 4 walls like this:

type alphatWallFunction;
value uniform 0;

The problem is that it appears this error:

PHP Code:

file: /home/jstoeckl/Desktop/grav0/0/alphat.boundaryField.Back from line 26 to line 27.

    From function fvPatchField<Type>::New(const fvPatch&, const DimensionedField<Type, volMesh>&, const dictionary&)
    in file /home/opencfd/OpenFOAM/OpenFOAM-2.3.0/src/finiteVolume/lnInclude/fvPatchFieldNew.C at line 143.

FOAM exiting 


I would really like to know how this parameter works. I think its value should be 0 in the solid parts (walls and sphere) and it has a different value in inlet and outlet From this I have my other doubts:
- How do I calculate this value for my incompressible fluid?
- How do I assign these 2 inputs? Should it be just with "fixedValue?


Thank you very much for your help