sunfluidh:fluid_properties

Namelist "Fluid_Properties"

Most of data are initialized with a default value that could be used by the code if this data is not set to the user's value.
Data are used or not depending on the context. For this reason, useless data could be omitted in the data set.
The user must therefore ensure that useful data are explicitly stated unless he is sure that the default value is correct (if there is any doubt, you can check the file named “check_namelist_data.dat”).
Some examples are given here for helping the user about this namelist.

Full data set of the Namelist

The values are arbitrary chosen.

 &Fluid_Properties  Variable_Density          = .true. , 
                 Incomp_Multifluids           = .false.   , 
                 Constant_Mass_Flow           = .false. , 
                 MultiSpecies_Flow            = .true. ,
                 Heat_Transfer_Flow           = .false.  ,
                  Heat_Capacity_Ratio         = 1.4  ,
                 Reference_Dynamic_Viscosity  = 1.84D-05 ,
                 Reference_Dynamic_Viscosity_2= 1.84D-05 , 
                 Reference_Density            = 1.2058789 ,
                 Reference_Density_2          = 0.4 ,
                 Surface_Tension_Coefficient  = 0.0 ,
                 Prandtl                      = 0.71 ,
                 Reference_Temperature        = 293.0    , 
                 Molecular_Mass               = 2.9D-02            ,
                 Thermal_Expansion_Coefficient= 0.0
                 Reference_Heat_Capacity      = 1000.00  ,
                 Sutherland_Law_Enabled                                    = .false.   ,
                 Multi_Species_Mixture_Law_for_Viscosity_Enabled           = .false. ,
                 Multi_Species_Mixture_Law_for_Thermal_Conductivity_Enabled= .false. ,
                 Multi_Species_Mixture_Law_for_Mass_Diffusion_Enabled      = .false.  ,
                 Soret_Effect_Enabled                                      = .false. ,
                 Axisymmetric_Case_3D_Enabled                              = .false. /

The reference values of physical quantities are used in different ways :

For incompressible flows with heat transfer, the “Reference_Temperature” is used to define the reference temperature implied in the buoyancy force (see the namelist "Gravity".
If the incompressible fluid is a gas, the “Reference_Temperature” can be also used by the code in order to calculate automatically the thermal expansion coefficient (for that, the user must set the variable “Thermal_Expansion_Coefficient” to zero).
For incompressible two-phase flows, the “Reference_Density” and the “Reference_Density_2” are used in order to initialize the density field. This field must be explicitly defined by an user's function in the module “module_user_define_init_fields.f90”. The dynamic viscosity field is automatically initialized from the data “Reference_Density” and “Reference_Density_2”.
For low Mach number flows, the reference pressure value is calculated from the “Reference_Density”, the “Reference_Temperature” and the “Molecular_Mass” by using the equation of state of perfect gas.
This pressure, that is uniform over the domain, is thus used for initializing the density field, knowing the temperature field (defined with the namelist "Temperature_Initialization") and the species mass fraction fields (defined with the namelist "Species_Initialization") in the particular case of multi-species flows.
For low Mach number flows or incompressible two-phase flows, the “Reference_Density” is also implied in the gravity/buoyancy force (see the namelist "Gravity".
The “Reference_Dynamic_Viscosity” must be in accordance with the “Reference_Temperature” when the viscosity depends on the temperature (Sutherland's law).

Find here some examples

Definition of the data set

Variable_Density

type : Boolean value
- true : low mach number hypothesis ( Not for the release SUNFLUIDH_EDU )
- false : incompressible flow
Default value = .false.

Incomp_MultiFluids

type : Boolean value ( Not for the release SUNFLUIDH_EDU )
- true : incompressible two-fluid flow (only whether Variable_Density=true).
- false : single phase flow
Default value = .false.

Constant_Mass_Flow

type = Boolean value
- true : mass conservation
- false : mass variation possible
Default value = .true.

Constant_Pressure_Flow

type = Boolean value
true : Thermodynamical pressure is imposed and constant
Default value = .false.

Variable_Fluid_Volume

type = Boolean value
- true : The volume of fluid can vary in time
Default value = .false.

MultiSpecies_Flow

type = boolean value
true : heterogeneous gas mixture ( Not for the release SUNFLUIDH_EDU )
false : homogeneous gas mixture
Default value = .false.

Heat_Transfer_Flow

type = boolean value
- true : flows with heat transfer
- false : isothermal flows
Default value = .false.

Reference_Temperature

type = real value
Reference value of the temperature
Default value= 300.0

Reference_Density

type = real value
reference value of the density
Default value = 1.0

Reference_Density_2

type = real value ( Not for the release SUNFLUIDH_EDU )
reference value of the 2nd fluid density for incompressible two-fluid flows (used with Incomp_MultiFluids= .true.)
Default value= 1.0

Reference_Dynamic_Viscosity

type = real value
Reference value of the dynamic viscosity (used if the viscosity is independent of the mixture components)
Default value = 1.84D-05

Reference_Dynamic_Viscosity_2

type = real value ( Not for the release SUNFLUIDH_EDU )
Reference value for the 2nd dynamic viscosity of incompressible two-fluid flows (used with Incomp_MultiFluids= .true.)
Default value= 1.84D-05

Surface_Tension_Coefficient

type = real value ( Not for the release SUNFLUIDH_EDU )
Surface tension coefficient for the simulation of two-fluid flows with capillary effects (used with Incomp_MultiFluids= .true.).
Default value = 0.0

Prandtl

type = real value
Prandtl number (used for calculating the thermal conductivity if it is independant of the mixture components)
Default value= 0.71

Molecular_Mass

type = real value
Reference value of the molecular mass (in kg/mol) of the fluid, this parameter is used if the fluid is a homogeneous gas defined in a low mach number context, without taking into account the mixture components. Equations and physical quantities are defined in a dimensional form.
Default value= 0.029

Thermal_Expansion_Coefficient

type = real value
This data is mainly used for incompressible flows, when the gravity/buoyancy force depends on the temperature variation.
If this variable is set to zero, it is automatically defined as 1/Reference_Temperature by the code - perfect gas hypothesis).
For low Mach number or incompressible two-phase flows, the gravity/buoyancy force depends on the density variation, this variable can thus be omitted.
See the namelist "Gravity" to understand how this variable is implemented in the gravity/buoyancy force.
Default value = 1.0.

Reference_Heat_Capacity

type = real value
Reference value of the mass heat capacity of the fluid.
This value is only used if the fluid is incompressible. Otherwise, it is calculated from the formulation for a perfect gas :
Cp= (R/Molecular_Mass)*(Heat_Capacity_Ratio/(Heat_Capacity_Ratio - 1)
where R is the perfect gas constant of perfect gas.

Sutherland_Law_Enabled

type : boolean value
true : The Sutherland 's law is used to calculate the viscosity and the thermal conductivity in respect with the temperature only. Mixture components are not considered)
false : The Sutherland's law is not activated
Default value = .false.

Multi_Species_Mixture_Law_for_Viscosity_Enabled

type : boolean value ( Not for the release SUNFLUIDH_EDU )
true : The dynamic viscosity is defined from the mixture components and temperature (from the kinetic gas theory)
false : The dynamic viscosity is defined from the Sutherland's law or is constant
Default value = .false.

Multi_Species_Mixture_Law_for_Thermal_Conductivity_Enabled

type : boolean value ( Not for the release SUNFLUIDH_EDU )
true : The thermal conductivity is defined from the mixture components and temperature (from the kinetic gas theory)
false : The thermal conductivity is defined from the Sutherland's law or is constant
Default value = .false.

Multi_Species_Mixture_Law_for_Mass_Diffusion_Enabled

type : boolean value ( Not for the release SUNFLUIDH_EDU )
true : The species diffusion coefficients are defined from the mixture components and temperature (from the kinetic gas theory)
false : The species diffusion coefficients are calculated from the Schmidt number
Default value = .false.

Soret_Effect_Enabled

type : boolean value ( Not for the release SUNFLUIDH_EDU )
the Soret mass diffusion is considered (flow with multi-components gas and temperature gradients)
Default value = .false.

Axisymmetric_Case_3D_Enabled

type : boolean value
true : the third velocity component is taken in to account for a 2D axisymmetric problem (You must set Geometric_Layout = 2)
false: the third velocity component is not taken in to account for a 2D axisymmetric problem
Default value = .false.

Table des matières