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Examples of data set related to the namelist "Fluid_Properties".
The user finds here some examples illustrating different configurations related to the namelist "Fluid_Properties". The data initialized by default, and not explicitly required, are generally not present for a sake of clarity.
Data values are showed for equations used in dimensional form.
Monophasic incompressible Flows with constant physical properties
Without heat transfer
&Fluid_Properties Reference_Dynamic_Viscosity = 1.84D-05 ,
Reference_Density = 1.2058789 /
With heat transfer and buoyancy force
&Fluid_Properties Reference_Dynamic_Viscosity = 1.84D-05 ,
Prandtl = 0.71 ,
Reference_Temperature = 300.0 ,
Reference_Density = 1.20 ,
Thermal_Expansion_Coefficient= 0.033
Reference_Heat_Capacity = 1004.50 /
Note: For incompressible flows with buoyancy force, don not forget to define the “Thermal_Expansion_Coefficient” because the buoyancy force is defined from the temperature variation in place of the density.
Thermal_Expansion_Coefficient= 0.0 involves that it is automatically calculated as the inverse of the “Reference_Temperature”.
The “Reference_Heat_Capacity” is only useful when the simulation must explicitly take into account the heat flux (i.e. a heat flux boundary condition or heat exchange between the fluid and a thermal conductive material).
In these cases, the equation of enthalpy is globally considered and not its simplified version that leads to the equation of temperature.
Example of Axisymmetric flows
&Fluid_Properties Axisymmetric_Case_3D_Enabled= .true. ,
Reference_Dynamic_Viscosity = 1.84D-05 ,
Prandtl = 0.71 ,
Reference_Temperature = 300.0 ,
Reference_Density = 1.20 ,
Thermal_Expansion_Coefficient= 0.033
Reference_Heat_Capacity = 1004.50 /
Note : In this case, do not forget to define the domain in cylindrical geometry (see the Namelist "Domain_Features" ).
Incompressible two phase flows without heat transfer (physical properties of each fluid is constant)
&Fluid_Properties Incomp_MultiFluids= .true. ,
Reference_Dynamic_Viscosity = 1.84D-05 ,
Reference_Dynamic_Viscosity_2 = 1.00D-03 ,
Reference_Density = 1.2 ,
Reference_Density_2 = 1000. ,
Interface_Thickness_Scale = 1.e-2 ,
Incomp_MultiFluids/
Low Mach-number Flows (perfect gas only)
Flows with heat transfer (one species only, viscosity depends on the Sutherland's law)
&Fluid_Properties Variable_Density = .true. ,
Reference_Dynamic_Viscosity = 1.84D-05 ,
Reference_Temperature = 300.0 ,
Reference_Density = 1.20 ,
Prandtl = 0.71 ,
Heat_Capacity_Ratio = 1.4 ,
Molecular_Mass = 2.9D-02 ,
Reference_Heat_Capacity = 1004.50 ,
Sutherland_Law_Enabled = .true. /
In the dimensionless form, the specific gas constant is generally equal to unity and the heat capacity is $C_p= \frac{\gamma}{\gamma -1}$. The reference value of the molecular mass must be set to the constant of perfect gas $R$.
If gravity/buoyancy effects must be considered, they are directly bounded to the density variation. The variable “Thermal_Heat_Expansion” can be omitted and the gravity source term can be defined in the namelist "Gravity".
Flows with heat transfer (multi-species gas , physical properties depend on the gas components
&Fluid_Properties Variable_Density = .true. ,
MultiSpecies_Flow = .true. ,
Reference_Dynamic_Viscosity = 1.84D-05 ,
Reference_Temperature = 300.0 ,
Reference_Density = 1.20 ,
Prandtl = 0.71 ,
Heat_Capacity_Ratio = 1.4 ,
Thermal_Expansion_Coefficient= 0.0 ,
Molecular_Mass = 2.9D-02 ,
Reference_Heat_Capacity = 1004.50 ,
Sutherland_Law_Enabled = .true.
Multi_Species_Mixture_Law_for_Viscosity_Enabled = .true. ,
Multi_Species_Mixture_Law_for_Thermal_Conductivity_Enabled= .true. ,
Multi_Species_Mixture_Law_for_Mass_Diffusion_Enabled = .true. ,
Soret_Effect_Enabled = .false. //
In this example, the physical properties are not constant depend on the gas mixture and the temperature. They are calculated in each cell for each time step by means of formualtions coming from the kinetic theory of gas.
The gas properties bounded to each species are provided by the namelist "Species_Properties".
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