[luhawk]

Hi everybody,

I am currently trying to implement the calculation of a cell face weighted Velocity average in flow direction as a dimensioned scalar. The cell face for weighting shall be the one at the defined boundary patch.

I tried:

dimensionedScalar weightedVelocity = (flowDirection & U)().weightedAverage(mesh.boundary()[patchID].Sf());

but the prompt (as I interpret it) says that weightedAverage will only accept a volume Mesh field not a field:

error: no matching function for call to ‘Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>::weightedAverage(const Foam::Field<Foam::Vector<double> >&)’
/opt/OpenFOAM/OpenFOAM-2.1.0/src/OpenFOAM/lnInclude/DimensionedField.C:381: note: candidates are: Foam::dimensioned<Type> Foam::DimensionedField<Type, GeoMesh>::weightedAverage(const Foam::DimensionedField<double, GeoMesh>&) const [with Type = double, GeoMesh = Foam::volMesh]
/opt/OpenFOAM/OpenFOAM-2.1.0/src/OpenFOAM/lnInclude/DimensionedField.C:399: note:                 Foam::dimensioned<Type> Foam::DimensionedField<Type, GeoMesh>::weightedAverage(const Foam::tmp<Foam::DimensionedField<double, GeoMesh> >&) const [with Type = double, GeoMesh = Foam::volMesh]

so I tried using fvc::average as follows:

dimensionedScalar weightedVelocity = average(flowDirection & U.boundaryField()[patchID]);

It compiles but when i run the code i get the dimension error:

--> FOAM FATAL ERROR: 
LHS and RHS of - have different dimensions
     dimensions : [0 1 -1 0 0 0 0] - [0 0 0 0 0 0 0]

where weightedVelocity is the RHS. So my question is why do i loose the dimension when averaging or are there any other ideas to get the weighted average?

Thanks for your answers,

Cheers Lu