[edwinrajeev]

Hi all,
I am currently running a 3D VOF simulation to study wave interaction with a breakwater structure. I intend to use AMR to refine the interface only in the breakwater region and not the entire domain.

Is it possible to use topoSet to define the region and use AMR only on the prescribed cell set?

Thank you and Regards

[clapointe]

It is -- I've done something similar in the past, well the opposite, really, but it gets the job done if I remember correctly. Based on code from PDRFoam (the amr version) we can protect some initial cell set from refinement (this way the cell set doesn't need to be updated as the mesh changes, because it shouldn't change). It looks something like this :

    // Test : disable refinement for some cells
    PackedBoolList& protectedCell = refCast<dynamicRefineBalanceMultiRegionFvMesh>(mesh).protectedCell();

    if (protectedCell.empty())
    {
        protectedCell.setSize(mesh.nCells());
        protectedCell = 0;
    }

        cellSet protectedCells
        (
            IOobject
            (
                "protectedCells",
                "constant/polyMesh/sets",
                mesh,
                IOobject::MUST_READ,
                IOobject::NO_WRITE
            )
        );

        forAll (mesh.C(), celli)
        {
            if (protectedCells[celli])
            {
                protectedCell[celli] = 1;
            }
        }

That code would go before the mesh.update() call inside the solver (you can also use a custom bool to toggle the option). I imagine you could put it inside dynamicRefineMesh too, but I've not bothered.

Caelan

[edwinrajeev]

Thank you so much Caelan. This is great. I will try and implement this in waves2Foam and see if it works properly.

Additionally, as you mentioned what would be your suggestion on implementing this in dynamicRefineMesh? This could be quite a handy tool from a general standpoint.

Thanks

[clapointe]

Off the top of my head, you'd likely add similar code to the initialization bit of the dynamicRefineFvMesh code -- simply updating the protectedCells list inside there instead of on the solver end.

Caelan

[jairoandres]

Thank you a lot. I want to mention that I tested the code (used parts of it you placed in another forum thread), which worked well under sprayFoam (or sprayDyMFoam) in OpenFOAM V2012.

Requirements:

1. to #include "dynamicRefineFvMesh.H" just after the base library is included (dynamicFvMesh)
2. to #include "cellSet.H"
3. This part of the code "protectedCells" is the name of the cellSet you are creating in toposetDict:

cellSet protectedCells

4. The given code was OK for running on a single processor. Under parallel processing, I had to replace the location of the original cellSet after decomposition: ie:

    "protectedCells",
 "6e-05/polyMesh/sets",

It is not very practical, but it worked well. In this case, 6e-05 was the name of the folder created by snappyHexMesh when prerefining a structured mesh created with blockMeshDict. Otherwise, the solver could not find the folder "constant" as it was not created for each processor. Maybe someone else can come out with a better solution.

Here is the complete piece of code:

    bitSet& protectedCell = refCast<dynamicRefineFvMesh>(mesh).protectedCell();

if (protectedCell.empty())
{
    protectedCell.setSize(mesh.nCells());
    protectedCell = false;
}


        cellSet protectedCells
        (
            IOobject
            (
                "protectedCells",
                "6e-05/polyMesh/sets",
                mesh,
                IOobject::MUST_READ,
                IOobject::NO_WRITE
            )
        );

        forAll (mesh.C(), celli)
        {
            if (protectedCells[celli])
            {
                protectedCell[celli] = 1;
            }
        }

Again, my thanks. Best regards,

J.A. Gutiérrez.

Ps: Last piece of advice: Remember you can add multiple regions to the same cellSet using "new" for the first and then "add" for the other definitions, i.e.:

    {
        name    protectedCells;
        type    cellSet;
        action  new;
        source      cylinderToCell;
       p1         (0 0 0);
       p2         (0 -0.5 0);
       radius          0.125;
    }

 {
        name    protectedCells;
        type    cellSet;
        action  add;
        source      cylinderToCell;
       p1         (0 0 0);
       p2         (0 -0.2 0);
       radius          0.19;
       }