Box Refinement

The box refinement section allows for a specific region in the grid to be finer before the simulation starts. To do so, a box refinement can be added with the following example parameters:

subsection box refinement
  subsection mesh
    set type               = dealii
    set grid type          = subdivided_hyper_rectangle
    set grid arguments     = 1,1,1 : -1,-1,-1 : 1,1,1 : true
    set initial refinement = 0
  end
  set initial refinement = 3
end

• The mesh subsection allows to define the region in which the fluid mesh needs to be refined. A cell will be refined if at least one of its degrees of freedom (dofs) is located within the outer boundaries of the box specified in the grid arguments. Therefore, in this example, every cell of the fluid mesh that has at least one of its dofs located in the hexahedron located between (-1, -1, -1) and (1,1,1) will be refined. For more information on meshes, see Mesh.

Tip

The initial refinement of the subdivided_hyper_rectangle should be as small as possible, since the initial refinement of the box mesh itself will not have any impact on the definition of the refinement zone.

Note

The used mesh can be of any type and any grid type.

• The initial refinement parameter in the box refinement subsection will dictate the number of times the cells inside the box will be refined.