[gbettega]

Hello forum,
a mixture of three components: see below,
with species transport active.

% ------------------------------------------
% Fluid mixture definition
% ------------------------------------------
FLUID_MODEL= FLUID_MIXTURE
INC_DENSITY_MODEL= VARIABLE
INC_ENERGY_EQUATION= YES
MOLECULAR_WEIGHT= ( 28.964700, 28.964700, 28.964700 )
SPECIFIC_HEAT_CP= ( 1004.700000, 1004.700000, 1004.700000 )
% ------------------------------------------
% Mixture thermal conductivity model
% ------------------------------------------
CONDUCTIVITY_MODEL= CONSTANT_PRANDTL
PRANDTL_LAM= ( 0.710000, 0.710000, 0.710000 )
PRANDTL_TURB= ( 0.900000, 0.900000, 0.900000 )
TURBULENT_CONDUCTIVITY_MODEL= CONSTANT_PRANDTL_TURB
% ------------------------------------------
% Mixture viscosity model
% ------------------------------------------
VISCOSITY_MODEL= CONSTANT_VISCOSITY
MU_CONSTANT= ( 0.000017, 0.000017, 0.000017 )
MIXING_VISCOSITY_MODEL= WILKE

KIND_SCALAR_MODEL= SPECIES_TRANSPORT
%KIND_SCALAR_MODEL= NONE

% ------------------------------------------
% Mixture diffusivity model
% ------------------------------------------
DIFFUSIVITY_MODEL= CONSTANT_DIFFUSIVITY
DIFFUSIVITY_CONSTANT= 0.001000
CONV_NUM_METHOD_SPECIES= BOUNDED_SCALAR
MUSCL_SPECIES= NO
SLOPE_LIMITER_SPECIES= NONE
TIME_DISCRE_SPECIES= EULER_IMPLICIT
CFL_REDUCTION_SPECIES= 1.0

SPECIES_INIT= ( 0.333333, 0.333333 )

SPECIES_CLIPPING= NO
SPECIES_CLIPPING_MAX= ( 1.0, 1.0 )
SPECIES_CLIPPING_MIN= ( 0.0, 0.0 )


Now,

KIND_SCALAR_MODEL= SPECIES_TRANSPORT

needs

SPECIES_INIT= ( 0.333333, 0.333333 )

If I use (commenting SPECIES_INIT)

KIND_SCALAR_MODEL= NONE
%SPECIES_INIT= ( 0.333333, 0.333333 )

the solver outputs an error,

Error in "void CConfig::SetPostprocessing(SU2_COMPONENT, short unsigned int, short unsigned int)":
-------------------------------------------------------------------------
The use of FLUID_MIXTURE requires the number of entries for MOLECULAR_WEIGHT and SPECIFIC_HEAT_CP,
to be equal to the number of entries of SPECIES_INIT + 1
------------------------------ Error Exit -------------------------------


Now, if I use (reactivate SPECIES_INIT)

KIND_SCALAR_MODEL= NONE
SPECIES_INIT= ( 0.333333, 0.333333 )

the solver runs and reaches a certain convergence level.

Species_0 Diffusivity_0, Species_1 Diffusivity_1 are removed from the results output.
KIND_SCALAR_MODEL is NONE (off) and FLUID_MODEL= FLUID_MIXTURE

Quqestion: what's happening? Which fluid is SU2 simulating? A mixture, one component of the mixture?

Grazie mille
Giovanni

[cristopher_morales]

Originally Posted by gbettega

Hello forum,
a mixture of three components: see below,
with species transport active.

% ------------------------------------------
% Fluid mixture definition
% ------------------------------------------
FLUID_MODEL= FLUID_MIXTURE
INC_DENSITY_MODEL= VARIABLE
INC_ENERGY_EQUATION= YES
MOLECULAR_WEIGHT= ( 28.964700, 28.964700, 28.964700 )
SPECIFIC_HEAT_CP= ( 1004.700000, 1004.700000, 1004.700000 )
% ------------------------------------------
% Mixture thermal conductivity model
% ------------------------------------------
CONDUCTIVITY_MODEL= CONSTANT_PRANDTL
PRANDTL_LAM= ( 0.710000, 0.710000, 0.710000 )
PRANDTL_TURB= ( 0.900000, 0.900000, 0.900000 )
TURBULENT_CONDUCTIVITY_MODEL= CONSTANT_PRANDTL_TURB
% ------------------------------------------
% Mixture viscosity model
% ------------------------------------------
VISCOSITY_MODEL= CONSTANT_VISCOSITY
MU_CONSTANT= ( 0.000017, 0.000017, 0.000017 )
MIXING_VISCOSITY_MODEL= WILKE

KIND_SCALAR_MODEL= SPECIES_TRANSPORT
%KIND_SCALAR_MODEL= NONE

% ------------------------------------------
% Mixture diffusivity model
% ------------------------------------------
DIFFUSIVITY_MODEL= CONSTANT_DIFFUSIVITY
DIFFUSIVITY_CONSTANT= 0.001000
CONV_NUM_METHOD_SPECIES= BOUNDED_SCALAR
MUSCL_SPECIES= NO
SLOPE_LIMITER_SPECIES= NONE
TIME_DISCRE_SPECIES= EULER_IMPLICIT
CFL_REDUCTION_SPECIES= 1.0

SPECIES_INIT= ( 0.333333, 0.333333 )

SPECIES_CLIPPING= NO
SPECIES_CLIPPING_MAX= ( 1.0, 1.0 )
SPECIES_CLIPPING_MIN= ( 0.0, 0.0 )


Now,

KIND_SCALAR_MODEL= SPECIES_TRANSPORT

needs

SPECIES_INIT= ( 0.333333, 0.333333 )

If I use (commenting SPECIES_INIT)

KIND_SCALAR_MODEL= NONE
%SPECIES_INIT= ( 0.333333, 0.333333 )

the solver outputs an error,

Error in "void CConfig::SetPostprocessing(SU2_COMPONENT, short unsigned int, short unsigned int)":
-------------------------------------------------------------------------
The use of FLUID_MIXTURE requires the number of entries for MOLECULAR_WEIGHT and SPECIFIC_HEAT_CP,
to be equal to the number of entries of SPECIES_INIT + 1
------------------------------ Error Exit -------------------------------


Now, if I use (reactivate SPECIES_INIT)

KIND_SCALAR_MODEL= NONE
SPECIES_INIT= ( 0.333333, 0.333333 )

the solver runs and reaches a certain convergence level.

Species_0 Diffusivity_0, Species_1 Diffusivity_1 are removed from the results output.
KIND_SCALAR_MODEL is NONE (off) and FLUID_MODEL= FLUID_MIXTURE

Quqestion: what's happening? Which fluid is SU2 simulating? A mixture, one component of the mixture?

Grazie mille
Giovanni

Hi Giovanni,

Thank you so much for your question, when the KIND_SCALAR_MODEL=NONE, it means that you are not solving the species transport equations, that is why you do not get the following output: Species_0 Diffusivity_0, Species_1 Diffusivity_1
In this case, the fluid model used is the default, which is CONTANT_DENSITY for incompressible flows, and you can check that the density output is the value of the constant density provided in the option INC_DENSITY_INIT.
I hope this helps, please let me know if you have any other doubt.

Best regards,

Cristopher Morales Ubal

[gbettega]

Thanks a lot Cristopher
for your support. I didn't read the code, so it was unclear for me
that the solution without species transport active referred to default fluid.
I needed it for tuning a Su2 GUI.
Regars
Giovanni