[Shibi]

Hello to all,


I would like to have some input on how to update the boundary values of a field.


I created a field called test:

        volScalarField test
        (
            IOobject
            (
                "test",
                runTime.timeName(),
                mesh,
                IOobject::MUST_READ,
                IOobject::AUTO_WRITE
            ),
            mesh,
            dimensionedScalar("test_", dimless, 2)
        );

The boundary conditions for test are fixedValue for all patches with a value of 2.

dimensions      [0 0 0 0 0 0 0];


internalField   uniform 0;

boundaryField
{
    "(.*)"
    {
        type            fixedValue;
        value           uniform 2;
    }

}

I perform some arithmetic with this field:

test = test+test

If I specify to write the field I will get:

test.write();

dimensions      [0 0 0 0 0 0 0];


internalField   uniform 4;

boundaryField
{
    myPatch1
    {
        type            calculated;
        value           uniform 4;
    }
myPatch2
    {
        type            calculated;
        value           uniform 4;
    }
myPatch3
    {
        type            calculated;
        value           uniform 4;
    }
myPatch4
    {
        type            calculated;
        value           uniform 4;
    }
myPatch5
    {
        type            calculated;
        value           uniform 4;
    }
}

Now, I would like to update the boundary values of test.

How can I do this?
I could just loop over the patch faces and adjust the value but is there a function for this?

If I try:

test.correctBoundaryConditions();

I will get the same output as before (all values at 4). I was hoping to get the values of the patches to be 2.

Can anyone clarify this ?

[gionni]

I don't know the answer but I have an idea.
As you know, a field has a boundary (list of boundary faces) and an internal field (list of cells).
Maybe you could try to sum the internal fields instead of the whole fields.

I had a similar problem anyway, and I just ended up cycling on the cells.

[Shibi]

Originally Posted by gionni

I don't know the answer but I have an idea.
As you know, a field has a boundary (list of boundary faces) and an internal field (list of cells).
Maybe you could try to sum the internal fields instead of the whole fields.

I had a similar problem anyway, and I just ended up cycling on the cells.

That is a fix, but I would like to know why this happens.



In the PEqn of a lot of solvers you see: Some operation on U followed by the update of the boundary conditions:


e.g., in PISO foam

U = HbyA - rAU*fvc::grad(p);
U.correctBoundaryConditions();

You can also see this applied to p_ rhg in several solvers.

I would like to know what it is doing (or what I did wrong in calling it), since the function call 3 functions:

    this->setUpToDate();    

    storeOldTimes();
     boundaryField_.evaluate();