[tehache]

Dear AllOfYou,

Based on the existing fixedGradient boundary condition, I am trying to implement a boundary condition for thermal radiation against an environment temperature, i.e.

gradient=eps*sigma/lambda*(TRef^4-Tf^4)

eps=emissivity, lambda=thermal conductivity, sigma=Stefan-Boltzmann-constant, TRef=environment temp., Tf= boundary face temp.

However, I cant multiply fields (for T^4). I tried to calculate TRef_*TRef_, as a first step, TRef_ beeing declared as Field<type> ... , same as gradient.
TRef_*=TRef gives a compiler error, telling me there is no operator *= taking as argument a
Foam::radFluxFvPatchField<foam::vector<double> >
(I made a radFluxFvPatchField from the fixedGradientFvPatchField..)
No wonder, there is no such operator ... but why is my FvPatchField parameterized with Type = Foam::Vector<double> ? It belongs to a VolScalarField (Temperature), the dictionary looks like this:

FoamFile
{
....

class volScalarField;
object T;
}

dimensions [0 0 0 1 0 0 0];

internalField nonuniform List<scalar>
.....

The boundary file like this:

boundaryField
{
top
{
type radFlux;
gradient uniform 100;
reftemp uniform 1710;

.....


So, I expected to get Type=double, and to have a field of doubles. Apparently, I have however a field of vectors of doubles.
Probably I got something completely wrong ... please enlighten me !

(Btw., if I just specify the gradient, the implementation works)