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Table des matières
Rules of construction
Click here to come back to the "Heat_Wall_Boundary_Condition_Setup"
Click here to come back to the "Velocity_Wall_Boundary_Condition_Setup"
Click here to come back to the "Species_Wall_Boundary_Condition_Setup"
Click here to come back to the "Polyhedral_Immersed_Bodies"
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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 Pool” (WBCP) :
- The enthalpy or temperature : Namelist "Heat_Wall_Boundary_Condition_Setup"
- The velocity components : Namelist "Velocity_Wall_Boundary_Condition_Setup"
- The species mass fractions : 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) :
The following points are really important to understand how to construct the wall boundary conditions.
- A full set of wall boundary conditions (“WBCP”) 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 WBCP defined in the data file. The link is made by means of the variable 'Wall_BC_DataSetName' belonging here to the namelists "Polyhedral_Immersed_Bodies" or "Cylindrical_Immersed_Bodies". This variable must match with these ones of the namelists "Heat_Wall_Boundary_Condition_Setup", "Velocity_Wall_Boundary_Condition_Setup" or "Species_Wall_Boundary_Condition_Setup".
- The walls placed at the ends of the domain are always linked to the WBCP whom Wall_BC_DataSetName= “Set1”.
- Differents IBC can be linked to the same WBCP in order to prevent any redundant WBCP 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 "Species_Wall_Boundary_Condition_Setup" can be omitted.
- For any case without thermal transfer, the 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 "Heat_Wall_Boundary_Condition_Setup" can be removed.
- For no-slip and impermeability conditions, the namelist "Velocity_Wall_Boundary_Condition_Setup" can be removed.
- For no wall effect on species (zero gradient condition), "Species_Wall_Boundary_Condition_Setup" can be removed.
Examples of wall boundary conditions
The user finds here some examples illustrating the construction of the wall boundary conditions.
- A 2D geometrical configuration is considered. So, data associated to the 3rd direction K could be removed. They are still kept in these examples even if they are useless.
- For the sake of clarity, the multi-species case is not considered (homogeneous fluid). The namelist associated to the species is therefore not present.
Heated enclosed cavity
- The domain is a square cavity (2D geometry).
- Bottom and top walls are insulated. The heat flux is null.
- The left wall is set to the upper constant and uniform temperature : T= 305K.
The right wall is set to the lower constant and uniform “temperature : T= 295K. - The velocity boundary conditions are no-slip and impermeability conditions.
- There is no immersed body.
- Walls of the cavity are located at the ends of the domain. This is the basic domain configuration initialized by the code if any other boundary condition is not placed at the ends (like inlet, outlet, symmetrical or periodical boundary conditions, see namelists Inlet_Boundary_Condition, Outlet_Boundary_Condition, or Border_Domain_Boundary_Conditions).
We need just to state one WPCP.
&Heat_Wall_Boundary_Condition_Setup Wall_BC_DataSetName ="Set1", West_Heat_BC_Option = 0 , East_Heat_BC_Option = 0 , Back_Heat_BC_Option = 1 , Front_Heat_BC_Option = 1 , South_Heat_BC_Option = 0 , North_Heat_BC_Option = 0, West_Heat_Function_Type= 0 , East_Heat_Function_Type= 0 , Back_Heat_Function_Type= 0 , Front_Heat_Function_Type= 0 , South_Heat_Function_Type= 0 , North_Heat_Function_Type= 0, West_Wall_BC_Value= 305. , East_Wall_BC_Value= 295. , Back_Wall_BC_Value= 0.0 , Front_Wall_BC_Value= 0.0 , South_Wall_BC_Value= 0.0 , North_Wall_BC_Value= 0.0 / &Velocity_Wall_Boundary_Condition_Setup Wall_BC_DataSetName ="Set1", West_Velocity_I_BC_Option= 0 , East_Velocity_I_BC_Option= 0 , Back_Velocity_I_BC_Option= 0 , Front_Velocity_I_BC_Option= 0, South_Velocity_I_BC_Option= 0 , North_Velocity_I_BC_Option= 0 , West_Velocity_J_BC_Option= 0 , East_Velocity_J_BC_Option= 0 , Back_Velocity_J_BC_Option= 0 , Front_Velocity_J_BC_Option= 0, South_Velocity_J_BC_Option= 0 , North_Velocity_J_BC_Option= 0 , West_Velocity_K_BC_Option= 0 , East_Velocity_K_BC_Option= 0 , Back_Velocity_K_BC_Option= 0 , Front_Velocity_K_BC_Option= 0, South_Velocity_K_BC_Option= 0 , North_Velocity_K_BC_Option= 0 , West_Velocity_I_Function_Type= 0, East_Velocity_I_Function_Type= 0, Back_Velocity_I_Function_Type= 0, Front_Velocity_I_Function_Type= 0, South_Velocity_I_Function_Type= 0, North_Velocity_I_Function_Type= 0 , West_Velocity_J_Function_Type= 0, East_Velocity_J_Function_Type= 0, Back_Velocity_J_Function_Type= 0, Front_Velocity_J_Function_Type= 0, South_Velocity_J_Function_Type= 0, North_Velocity_J_Function_Type= 0 , West_Velocity_K_Function_Type= 0, East_Velocity_K_Function_Type= 0, Back_Velocity_K_Function_Type= 0, Front_Velocity_K_Function_Type= 0, South_Velocity_K_Function_Type= 0, North_Velocity_K_Function_Type= 0 , West_Wall_Velocity_I= 0.0 , East_Wall_Velocity_I= 0.0 , Back_Wall_Velocity_I= 0.0 , Front_Wall_Velocity_I= 0.0 , South_Wall_Velocity_I= 0.0 , North_Wall_Velocity_I= 0.0 , West_Wall_Velocity_J= 0.0 , East_Wall_Velocity_J= 0.0 , Back_Wall_Velocity_J= 0.0 , Front_Wall_Velocity_J= 0.0 , South_Wall_Velocity_J= 0.0 , North_Wall_Velocity_J= 0.0 , West_Wall_Velocity_K= 0.0 , East_Wall_Velocity_K= 0.0 , Back_Wall_Velocity_K= 0.0 , Front_Wall_Velocity_K= 0.0 , South_Wall_Velocity_K= 0.0 , North_Wall_Velocity_K= 0.0 /
- There is just one WBCP. This name is “Set1”. It is automatically linked with the walls belonging to the domain ends.
- The no-slip and impermeable boundary conditions are actually used by default in the code. For this reason, this kind of boundary conditions could be not explicitly set.
Enclosed cavity with two bars
- The domain is a square cavity with a length of $L= 1.0$ (2D geometry).
- Walls of the cavity are set to the constant and uniform temperature : $T= 300 K$.
- Walls of the first bar are set to the constant and uniform heat flux : $Q= 5W/m^2$. Keep in mind that :
- heating the fluid from walls is defined with a negative heat flux
- cooling the fluid from walls is defined with a positive heat flux
- Walls of the second bar are set to the same boundary conditions as the cavity : $T=300 K$.
- The velocity boundary conditions are no-slip and impermeability conditions for all the walls (cavity and bars). As they correspond to the default boundary conditions, they are not explicitly stated here.
- There are two immersed bodies : the couple of bars. Each bar is a rectangle with a size of $0.1$x$0.2$. The center of the first bar is $0.3$x$0.3$, the second one is $0.7$x$0.7$
We need to two WBCP for setting the two different sets of wall boundary conditions, the first one for the imposed temperature, the second one for the imposed heat flux. We also need to state two IBD in order to define the positions of the couple of bars.
The first WBCP
&Heat_Wall_Boundary_Condition_Setup Wall_BC_DataSetName ="Set1", West_Heat_BC_Option = 0 , East_Heat_BC_Option = 0 , Back_Heat_BC_Option = 0 , Front_Heat_BC_Option = 0 , South_Heat_BC_Option = 0 , North_Heat_BC_Option = 0, West_Heat_Function_Type= 0 , East_Heat_Function_Type= 0 , Back_Heat_Function_Type= 0 , Front_Heat_Function_Type= 0 , South_Heat_Function_Type= 0 , North_Heat_Function_Type= 0, West_Wall_BC_Value= 300. , East_Wall_BC_Value= 300. , Back_Wall_BC_Value= 300.0 , Front_Wall_BC_Value= 300.0 , South_Wall_BC_Value= 0.0 , North_Wall_BC_Value= 0.0 /
The second WBCP
&Heat_Wall_Boundary_Condition_Setup Wall_BC_DataSetName ="Set2", West_Heat_BC_Option = 1 , East_Heat_BC_Option = 1 , Back_Heat_BC_Option = 1 , Front_Heat_BC_Option = 1 , South_Heat_BC_Option = 0 , North_Heat_BC_Option = 0, West_Heat_Function_Type= 0 , East_Heat_Function_Type= 0 , Back_Heat_Function_Type= 0 , Front_Heat_Function_Type= 0 , South_Heat_Function_Type= 0 , North_Heat_Function_Type= 0, West_Wall_BC_Value= -5.0 , East_Wall_BC_Value= -5.0 , Back_Wall_BC_Value= -5.0 , Front_Wall_BC_Value= -5.0 , South_Wall_BC_Value= 0.0 , North_Wall_BC_Value= 0.0 /
The first IBD (the first bar)
&Polyhedral_Immersed_Bodies Xi_1= 0.25 , Xj_1= 0.20 , Xk_1= 0.0 , Xi_2= 0.35 , Xj_2= 0.20 , Xk_2= 0.0 , Xi_3= 0.35 , Xj_3= 0.40 , Xk_3= 0.0 , Xi_4= 0.25 , Xj_4= 0.40 , Xk_4= 0.0 , Wall_BC_DataSetName ="Set2"/
The second IBD (the second bar)
&Polyhedral_Immersed_Bodies Xi_1= 0.65 , Xj_1= 0.60 , Xk_1= 0.0 , Xi_2= 0.75 , Xj_2= 0.60 , Xk_2= 0.0 , Xi_3= 0.75 , Xj_3= 0.80 , Xk_3= 0.0 , Xi_4= 0.65 , Xj_4= 0.80 , Xk_4= 0.0 , Wall_BC_DataSetName ="Set1"/
- The first immersed body is linked to the second WBCP(imposed heat flux) and the second body is linked to the first WBCP (imposed temperature) by means of the variable “Wall_BC_DataSetName”.
- The WBCP named “Set1” is also automatically linked to the walls of the domain end's (cavity walls).
- The rank order of the boundary conditions is unimportant.
Enclosed cavity with a thermally conductive bar
- The domain is a square cavity with a length of $L= 1.0$ (2D geometry).
- Bottom and top walls of the cavity are insulated. The heat flux is null.
- The left and right walls of the cavity are set to 305K and 295K, respectively.
- The bar is thermally conductive. Its size is $0.2$x$0.2$ and it is centered on the cavity.
- The velocity boundary conditions are no-slip and impermeable conditions for all walls.
We need to state two WBCP to define the two different sets of wall boundary conditions, the first one for the imposed temperature and heat flux at the walls of the cavity, the second one to define the physical properties of the bar. We also need to state one IBD in order to define the position of the bar.
The first WBCP
&Heat_Wall_Boundary_Condition_Setup Wall_BC_DataSetName ="Set1", West_Heat_BC_Option = 0 , East_Heat_BC_Option = 0 , Back_Heat_BC_Option = 1 , Front_Heat_BC_Option = 1 , South_Heat_BC_Option = 0 , North_Heat_BC_Option = 0, West_Heat_Function_Type= 0 , East_Heat_Function_Type= 0 , Back_Heat_Function_Type= 0 , Front_Heat_Function_Type= 0 , South_Heat_Function_Type= 0 , North_Heat_Function_Type= 0, West_Wall_BC_Value= 305. , East_Wall_BC_Value= 295. , Back_Wall_BC_Value= 0.0 , Front_Wall_BC_Value= 0.0 , South_Wall_BC_Value= 0.0 , North_Wall_BC_Value= 0.0 /
The second WBCP
&Heat_Wall_Boundary_Condition_Setup Wall_BC_DataSetName ="Set2", West_Heat_BC_Option = 2 , East_Heat_BC_Option = 2 , Back_Heat_BC_Option = 2 , Front_Heat_BC_Option = 2 , South_Heat_BC_Option = 0 , North_Heat_BC_Option = 0, Material_Thermal_Conductivity= 1.00 , Material_Mass_Heat_Capacity= 3000.00 , Material_Density= 900.00 /
The first IBD (the bar)
&Polyhedral_Immersed_Bodies Xi_1= 0.40 , Xj_1= 0.40 , Xk_1= 0.0 , Xi_2= 0.40 , Xj_2= 0.40 , Xk_2= 0.0 , Xi_3= 0.60 , Xj_3= 0.60 , Xk_3= 0.0 , Xi_4= 0.60 , Xj_4= 0.60 , Xk_4= 0.0 , Wall_BC_DataSetName ="Set2"/
- The WBCP named “Set1” is automatically linked to the walls of the domain end's (cavity walls).
- The bar (immersed body) is linked to the second WBCP.
Lid-driven cavity with a heated bar
The example is very similar to the previous one but the fluid is driven by the top wall of the cavity.
- The domain is a square cavity with a length of $L= 1.0$ (2D geometry).
- Bottom and top walls of the cavity are insulated. The heat flux is null.
- The left and right walls of the cavity are set to 305K and 295K, respectively.
- The bar is thermally conductive. Its size is $0.2$x$0.2$ and it is centered on the cavity.
- The velocity boundary conditions are no-slip and impermeability conditions for all walls except at the top of the cavity where $V= 1.5m.s^{-1}$. For these reason, the wall boundary conditions for the velocity must be stated.
We need to state two WBCP to define the two different sets of wall boundary conditions, the first one for the imposed temperature and heat flux at the walls of the cavity, the second one to define the physical properties of the bar. We also need to state one IBD in order to define the position of the bar.
The first WBCP
&Heat_Wall_Boundary_Condition_Setup West_Heat_BC_Option = 0 , East_Heat_BC_Option = 0 , Back_Heat_BC_Option = 1 , Front_Heat_BC_Option = 1 , South_Heat_BC_Option = 0 , North_Heat_BC_Option = 0, West_Heat_Function_Type= 0 , East_Heat_Function_Type= 0 , Back_Heat_Function_Type= 0 , Front_Heat_Function_Type= 0 , South_Heat_Function_Type= 0 , North_Heat_Function_Type= 0, West_Wall_BC_Value= 305. , East_Wall_BC_Value= 295. , Back_Wall_BC_Value= 0.0 , Front_Wall_BC_Value= 0.0 , South_Wall_BC_Value= 0.0 , North_Wall_BC_Value= 0.0 / &Velocity_Wall_Boundary_Condition_Setup West_Velocity_I_BC_Option= 0 , East_Velocity_I_BC_Option= 0 , Back_Velocity_I_BC_Option= 0 , Front_Velocity_I_BC_Option= 0, South_Velocity_I_BC_Option= 0 , North_Velocity_I_BC_Option= 0 , West_Velocity_J_BC_Option= 0 , East_Velocity_J_BC_Option= 0 , Back_Velocity_J_BC_Option= 0 , Front_Velocity_J_BC_Option= 0, South_Velocity_J_BC_Option= 0 , North_Velocity_J_BC_Option= 0 , West_Velocity_K_BC_Option= 0 , East_Velocity_K_BC_Option= 0 , Back_Velocity_K_BC_Option= 0 , Front_Velocity_K_BC_Option= 0, South_Velocity_K_BC_Option= 0 , North_Velocity_K_BC_Option= 0 , West_Velocity_I_Function_Type= 0, East_Velocity_I_Function_Type= 0, Back_Velocity_I_Function_Type= 0, Front_Velocity_I_Function_Type= 0, South_Velocity_I_Function_Type= 0, North_Velocity_I_Function_Type= 0 , West_Velocity_J_Function_Type= 0, East_Velocity_J_Function_Type= 0, Back_Velocity_J_Function_Type= 0, Front_Velocity_J_Function_Type= 0, South_Velocity_J_Function_Type= 0, North_Velocity_J_Function_Type= 0 , West_Velocity_K_Function_Type= 0, East_Velocity_K_Function_Type= 0, Back_Velocity_K_Function_Type= 0, Front_Velocity_K_Function_Type= 0, South_Velocity_K_Function_Type= 0, North_Velocity_K_Function_Type= 0 , West_Wall_Velocity_I= 0.0 , East_Wall_Velocity_I= 0.0 , Back_Wall_Velocity_I= 0.0 , Front_Wall_Velocity_I= 1.5 , South_Wall_Velocity_I= 0.0 , North_Wall_Velocity_I= 0.0 , West_Wall_Velocity_J= 0.0 , East_Wall_Velocity_J= 0.0 , Back_Wall_Velocity_J= 0.0 , Front_Wall_Velocity_J= 0.0 , South_Wall_Velocity_J= 0.0 , North_Wall_Velocity_J= 0.0 , West_Wall_Velocity_K= 0.0 , East_Wall_Velocity_K= 0.0 , Back_Wall_Velocity_K= 0.0 , Front_Wall_Velocity_K= 0.0 , South_Wall_Velocity_K= 0.0 , North_Wall_Velocity_K= 0.0 /
The second WBCP
&Heat_Wall_Boundary_Condition_Setup West_Heat_BC_Option = 2 , East_Heat_BC_Option = 2 , Back_Heat_BC_Option = 2 , Front_Heat_BC_Option = 2 , South_Heat_BC_Option = 0 , North_Heat_BC_Option = 0, Material_Thermal_Conductivity= 1.00 , Material_Mass_Heat_Capacity= 3000.00 , Material_Density= 900.00 / &Velocity_Wall_Boundary_Condition_Setup West_Velocity_I_BC_Option= 0 , East_Velocity_I_BC_Option= 0 , Back_Velocity_I_BC_Option= 0 , Front_Velocity_I_BC_Option= 0, South_Velocity_I_BC_Option= 0 , North_Velocity_I_BC_Option= 0 , West_Velocity_J_BC_Option= 0 , East_Velocity_J_BC_Option= 0 , Back_Velocity_J_BC_Option= 0 , Front_Velocity_J_BC_Option= 0, South_Velocity_J_BC_Option= 0 , North_Velocity_J_BC_Option= 0 , West_Velocity_K_BC_Option= 0 , East_Velocity_K_BC_Option= 0 , Back_Velocity_K_BC_Option= 0 , Front_Velocity_K_BC_Option= 0, South_Velocity_K_BC_Option= 0 , North_Velocity_K_BC_Option= 0 , West_Velocity_I_Function_Type= 0, East_Velocity_I_Function_Type= 0, Back_Velocity_I_Function_Type= 0, Front_Velocity_I_Function_Type= 0, South_Velocity_I_Function_Type= 0, North_Velocity_I_Function_Type= 0 , West_Velocity_J_Function_Type= 0, East_Velocity_J_Function_Type= 0, Back_Velocity_J_Function_Type= 0, Front_Velocity_J_Function_Type= 0, South_Velocity_J_Function_Type= 0, North_Velocity_J_Function_Type= 0 , West_Velocity_K_Function_Type= 0, East_Velocity_K_Function_Type= 0, Back_Velocity_K_Function_Type= 0, Front_Velocity_K_Function_Type= 0, South_Velocity_K_Function_Type= 0, North_Velocity_K_Function_Type= 0 , West_Wall_Velocity_I= 0.0 , East_Wall_Velocity_I= 0.0 , Back_Wall_Velocity_I= 0.0 , Front_Wall_Velocity_I= 0.0 , South_Wall_Velocity_I= 0.0 , North_Wall_Velocity_I= 0.0 , West_Wall_Velocity_J= 0.0 , East_Wall_Velocity_J= 0.0 , Back_Wall_Velocity_J= 0.0 , Front_Wall_Velocity_J= 0.0 , South_Wall_Velocity_J= 0.0 , North_Wall_Velocity_J= 0.0 , West_Wall_Velocity_K= 0.0 , East_Wall_Velocity_K= 0.0 , Back_Wall_Velocity_K= 0.0 , Front_Wall_Velocity_K= 0.0 , South_Wall_Velocity_K= 0.0 , North_Wall_Velocity_K= 0.0 , End_of_Data_Block= .true. /
The first IBD (the bar)
&Polyhedral_Immersed_Bodies Xi_1= 0.40 , Xj_1= 0.40 , Xk_1= 0.0 , Xi_2= 0.40 , Xj_2= 0.40 , Xk_2= 0.0 , Xi_3= 0.60 , Xj_3= 0.60 , Xk_3= 0.0 , Xi_4= 0.60 , Xj_4= 0.60 , Xk_4= 0.0 , Wall_BC_DataSetName ="Set2"/
- The first WBCP is automatically linked to the walls of the domain end's (cavity walls). The wall temperatures are imposed as in the previous case. Moreover the I-velocity component is set to 1.5 at the top wall (Front_Wall_Velocity_I= 1.5).
- The bar (immersed body) is linked to the second WBCP. The usual no-slip and impermeability boundary conditions are explicitly stated here because the default values are no longer available due to the previous WBCP.
- When several WBCP are present and at least one of them contains a specific set of velocity boundary conditions, which differ from the usual ones, the namelist "Velocity_Wall_Boundary_Condition_Setup" must then be explicitly set for each WBCP, even for the usual velocity boundary conditions.
Click here to come back to the "Heat_Wall_Boundary_Condition_Setup"
Click here to come back to the "Velocity_Wall_Boundary_Condition_Setup"
Click here to come back to the "Species_Wall_Boundary_Condition_Setup"
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