[impecca]

Dear Foamers,
I am trying to modify the nuSgsWallFunction (nuSgsUSpaldingWallFunctionFvPatchScalarField.C) in OF 1.7.1 and I got some questions.

I want to implement Wang & Moin ( pof.aip.org/resource/1/phfle6/v14/i7/p2043_s1 ) model. In this model it specifies tauw (wall shear stress) directly rather than nuSgs (like in 'nuSgsWallFunction'). So I managed to acess to the 'tauw' (B() in LES model, see the code below) as a first step but I do not know how I return a calculated values into the B().
I just added few more lines within the nuSgsUSpaldingWallFunctionFvPatchScalarField.C file.

// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //

void nuSgsWallFunctionFvPatchScalarField::evaluate
(
const Pstream::commsTypes
)
{
const scalarField& ry = patch().deltaCoeffs();

const fvPatchVectorField& U =
patch().lookupPatchField<volVectorField, vector>(UName_);

scalarField magUp = mag(U.patchInternalField() - U);

const scalarField& nuw =
patch().lookupPatchField<volScalarField, scalar>(nuName_);

//*** modification
const label patchI = patch().index();
const LESModel& lesModel =db().lookupObject<LESModel>("LESProperties");
fvPatchSymmTensorField& tauw= lesModel.B()().boundaryField()[patchI];

forAll(tauw, facei){
tauw[facei]=symmTensor(0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
}
//*** modification END


By this way, I got an error when I run a simulation which is

#0 Foam::error:: printStack(Foam::Ostream&)

It seems that 'tauw[facei]=symmTensor(0.0, 0.0, 0.0, 0.0, 0.0, 0.0)' has a problem. without this line, no error.
So could you suggest me how to return the calculated 'tauw' values into B() please? or any suggestion will be appreciated.

Thanks in advance.
Yusik