[emunoz]

Hi all,

I am solving a problem for which I need to update the boundary conditions in each iteration based on the same terms that the internal field uses.

The variable is:

volScalarField& Ui = Um[i];

I tried to change the boundary conditions (to a dummy value = 0.25) as:

/************************************************** *******/
forAll(Um[0].boundaryField(), patchi)
{
if(Um[0].boundaryField()[patchi].type() == "uniformFixedValue" )
{
forAll(Ui.boundaryFieldRef()[patchi], facei) //update
Ui.boundaryFieldRef()[patchi][facei] = 0.25;
}
}

Ui.boundaryFieldRef().updateCoeffs();

....

UiEqn.boundaryManipulate(Ui.boundaryFieldRef());

UiEqn.relax();

fvConstraints.constrain(UiEqn);

UiEqn.solve("Ui");

fvConstraints.constrain(Ui);

/************************************************** *******/

Even if Ui.boundaryField() is the desired during the "solve" part, the fvMatrix does not take into account this value but the value from the initialitation in the 0/Umdefault file.

I tried with "fixedValue" and "uniformFixedValue" boundary conditions but the result doesn't change.

Can anyone give me insights of how I can force my new boundary condition values in the fvMatrix UiEqn?

Thanks you all,

Eva

[olesen]

You are partly there but you need to adjust the boundary condition value with in boundary condition itself, not in the solver.
Probably best to use a uniformFixedValue as you have done, but use a coded type for the PatchFunction1 value. There are a few examples in the tutorials (you'll need to look). Your boundary condition may also lend itself to an expression for the PatchFunction1.

[emunoz]

Originally Posted by olesen

You are partly there but you need to adjust the boundary condition value with in boundary condition itself, not in the solver.
Probably best to use a uniformFixedValue as you have done, but use a coded type for the PatchFunction1 value. There are a few examples in the tutorials (you'll need to look). Your boundary condition may also lend itself to an expression for the PatchFunction1.

Thanks for your answer.
As I needed to use terms that were on the Eqn itself but the BC of Ui can not be imposed on the code, I solved it by creating an auxiliary variable.
That way, I imposed the BC I wanted for Ui in the variable aux_Ui, and I impose in the BC of Ui that it has to match the values of aux_Ui:

//////////////////

code #{
const fvPatch& boundaryPatch = patch();
const fvBoundaryMesh& boundaryMesh = boundaryPatch.boundaryMesh();
const fvMesh& mesh = patch().boundaryMesh().mesh();
const vectorField& Cf = boundaryPatch.Cf();
const label patchid = mesh.boundary().findPatchID(this->patch().name());

const volScalarField& aux_Ui((mesh.lookupObject<volScalarField>("aux_Um0 ")));
scalarField& field = *this;

forAll(Cf,faceI){
field[faceI]=aux_Ui.boundaryField()[patchid][faceI];
}
#};

////////////////

Thanks a lot for your valuable help