• Solver Fortran File: MMG2DSolver.F90
• Solver Name: ElmerIce_MeshAdapt2D(MMG2DSolver)
• Required Output Variable(s):
  • (1) dumy
• Required Input Variable(s):
  • (1) Metric
• Optional Output Variable(s): None
• Optional Input Variable(s): None

This is a pseudo solver (i.e. it is not solving an equation). This solver is used for the mesh adaptation (Mesh Adaptation).

This solver call the Mmg library (http://www.mmgtools.org/) to perform the mesh adaptation. This require to separately install the Mmg code. This solver is included only if the cmake arguments “MMG_INCLUDE_DIR” and “MMG_LIBRARY” are provided when compiling elmerice.

It will performed isotropic or anisotropic 2D mesh adaptation depending on the dofs of the Input Variable:

• If dofs=1, it must contain the required element size at the current node location
• If dofs=3, it must contain the components (M11,M22,M12) of the anisotropic metric (see Mesh Adaptation)

Our implementation is actually restricted to the adaptation of plane-view 2D meshes comprised of linear 3-nodes triangular elements.

Tested with Mmg master branch commit (6acfa9e7b20e41134d56af10eba1bb8fd1283f8f).

Solver 1
  Exec Solver = after timestep

  Equation = "MMG"
  Variable = -nooutput dumy
    Procedure = "ElmerIce_MeshAdapt2D" "MMG2DSolver"

!! Name of the adapted mesh (will be used to save the mesh on disk)
  Output file name = "square_aniso"

!! Name of the variable that contain the metric; 
  !! Anisotropic 2D mesh adaptation if M is of size 3 (M11,M22,M12)
  !! Isotropic 2D mesh adaptation if M is of size 1 
  Metric Variable Name = String "M" 
  

!! Mmg parameters (see Mmg documentation for more information)
  hausd = Real 1000.0 !Hausdorff parameter (controls the refinement near boundaries)
  hgrad = Real 1.3  !gradation value (controls the ratio between two adjacent edges)

  verbosity = Integer 10 !Mmg verbosity

End

Boundary condition sections must be present to affect a boundary condition Id to the new boundary elements.

Boundary Condition X
!! The adapted mesh boundary elements will receive the //Id//: **X**
  Target Boundaries = Y
End

An example for isotropic mesh adaptation can be found under [ELMER_TRUNK]/elmerice/Tests/MMG2D_Iso.
Examples for anisotropic mesh adaptation can be found under [ELMER_TRUNK]/elmerice/Tests/MMG2D_Aniso1 and [ELMER_TRUNK]/elmerice/Tests/MMG2D_Aniso2, where the mesh size is adapted using 1 or 2 variables (i.e. combining metric informations), respectively.