===== Rules of construction =====

[[sunfluidh:heat_wall_boundary_condition_setup_namelist|Click here to come back to the "Heat_Wall_Boundary_Condition_Setup"]] \\
[[sunfluidh:velocity_wall_boundary_condition_setup_namelist|Click here to come back to the "Velocity_Wall_Boundary_Condition_Setup"]] \\
[[sunfluidh:species_wall_boundary_condition_setup_namelist|Click here to come back to the "Species_Wall_Boundary_Condition_Setup"]] \\
[[sunfluidh:polyhedral_immersed_bodies_setup_namelist|Click here to come back to the "Polyhedral_Immersed_Bodies"]] \\
[[sunfluidh:cylindrical_immersed_bodies_setup_namelist|Click here to come back to the "Cylindrical_Immersed_Bodies"]] \\

The user finds here the elements in order to understand how to build the wall boundary conditions.\\
The wall boundary conditions are defined with different types of namelists :
   * The namelists describing the type of wall boundary conditions applied to different physical quantities (temperature,velocity, species). This group of namelist is here named the **"Wall Boundary Condition Type" __(WBCT)__** :
     * The enthalpy or temperature : [[sunfluidh:heat_wall_boundary_condition_setup_namelist|Namelist "Heat_Wall_Boundary_Condition_Setup"]]
     * The velocity components : [[sunfluidh:velocity_wall_boundary_condition_setup_namelist|Namelist "Velocity_Wall_Boundary_Condition_Setup"]]
     * The species mass fractions : [[sunfluidh:species_wall_boundary_condition_setup_namelist|Namelist "Species_Wall_Boundary_Condition_Setup"]]
   * The namelists defining the positions of walls that belong to the immersed bodies. Such a namelist is here named an **"Immersed body descriptor" __(IBD)__** :
     * [[sunfluidh:polyhedral_immersed_bodies_setup_namelist|Namelist "Polyhedral_Immersed_Bodies"]]
     * [[sunfluidh:cylindrical_immersed_bodies_setup_namelist|Namelist "Cylindrical_Immersed_Bodies"]]


**__The following points are really important to understand how to construct the wall boundary conditions.__**

<note important>
   * A full set of wall boundary conditions (**"WBCT"**) is created when the namelists related to the heat, velocity or species have got the same name, namely when the common variable 'Wall_BC_DataSetName' is set with the same character string (see examples below).
   * Each immersed body (**IBD**) has to be linked to one of the **WBCT** defined in the data file. The link is made by means of the variable 'Wall_BC_DataSetName' belonging here to the namelists [[sunfluidh:polyhedral_immersed_bodies_setup_namelist|"Polyhedral_Immersed_Bodies"]] or [[sunfluidh:cylindrical_immersed_bodies_setup_namelist|"Cylindrical_Immersed_Bodies"]]. This variable must match with these ones of the namelists [[sunfluidh:heat_wall_boundary_condition_setup_namelist|"Heat_Wall_Boundary_Condition_Setup"]], [[sunfluidh:velocity_wall_boundary_condition_setup_namelist|"Velocity_Wall_Boundary_Condition_Setup"]] or [[sunfluidh:species_wall_boundary_condition_setup_namelist|"Species_Wall_Boundary_Condition_Setup"]].
   * The walls placed at the ends of the domain are always linked to the **WBCT** whom Wall_BC_DataSetName= "Set1".
   * Differents **IBD** can be linked to the same **WBCT** in order to prevent any redundant **WBCT** in the data file.
   * The explicit setting of a namelist can be omitted if the physical quantity is not required in the simulation. For example :
       * For any case without multi-species fluids, the namelist [[sunfluidh:species_wall_boundary_condition_setup_namelist|"Species_Wall_Boundary_Condition_Setup"]] can be omitted.
       * For any case without thermal transfer, the namelist [[sunfluidh:heat_wall_boundary_condition_setup_namelist|"Heat_Wall_Boundary_Condition_Setup"]] can be omitted.
   * If an usual boundary condition are used for __**all the walls**__ of the geometrical configuration, the associated namelist can be removed. For example :
       * For adiabatic walls the namelist [[sunfluidh:heat_wall_boundary_condition_setup_namelist|"Heat_Wall_Boundary_Condition_Setup"]] can be removed.
       * For no-slip and impermeability conditions, the namelist [[sunfluidh:velocity_wall_boundary_condition_setup_namelist|"Velocity_Wall_Boundary_Condition_Setup"]] can be removed.
       * For no wall effect on species (zero gradient condition),  [[sunfluidh:species_wall_boundary_condition_setup_namelist|"Species_Wall_Boundary_Condition_Setup"]] can be removed.
</note>

===== Examples of wall boundary conditions  =====

[[sunfluidh:Examples_wall_bc |Click here to read them]]