Permeability block example

The permeability block example is a simple example of a flow through a porous media. The example is designed to show how to setup a simple case file and how to run a simulation using the Neko library. The example is located in the examples/permeability_block folder.

The example consists of a meshed square duct where a wall is placed inside. The wall is defined as a porous media with a given permeability. The flow is driven by a pressure difference between the inlet and the outlet.

The permeability is added as a volume force with a given value proportional to the local velocity. The permeability is defined as a scalar value and is added to the case file as a parameter.

$$ f(x) = - perm * u(x) $$

1. permeability_3: The permeability is set to 1000.
2. permeability_5: The permeability is set to 100000.
3. permeability_wall: The mesh is modified to include a wall boundary condition instead of a porous media.

Please note that due to size constraints the mesh is not included in the repository. However, the Cubit journal file is included in the data folder. The mesh can be generated using the journal file and the Cubit software, along with the Exo2Nek plugin from Nek5000. Please see the meshing documentation for details on how to generate the mesh: Meshing.