bool Foam::meshTriangulation::isInternalFace
(
    const primitiveMesh& mesh,
    const boolList& includedCell,
    const label faceI
)
{
    if (mesh.isInternalFace(faceI))
    {
        label own = mesh.faceOwner()[faceI];
        label nei = mesh.faceNeighbour()[faceI];

        if (includedCell[own] && includedCell[nei])
        {
            // Neighbouring cell will get included in subset
            // as well so face is internal.
            return true;
        }
        else
        {
            return false;
        }
    }
    else
    {
        return false;
    }
}