# 7.11. Initial Conditions

This section is referenced in the following other sections

- Simulation Setup: Initial Conditions

## 7.11.1. Initial Condition Block

Scope

  Fuego Region

Summary

  Allows the specification of piecewise constant initial conditions on any combination of volumes, surfaces and nodes.

    begin Initial Condition Block BlockName

        {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} Value

       Copy Nodal File Variable ExodusName To Region Field AfgoName [ At Time InterpTime  ]

       External Field For VariableName {=} ExtFieldName [ Of Size Value  ]

       External Field For Progress_Variable ProgressVariableName {=} ExtFieldName

       Function For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} FuncName In The {t | x | y | z} Direction

       Function For Mass_Fraction {=} FuncName In The {t | x | y | z} Direction

       Function For Mole_Fraction {=} FuncName In The {t | x | y | z} Direction

       Ignite

       Inline Function For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} FuncStr

       Integer Data For Subroutine SubName {=} Values...

       Mass_Fraction Species {=} y0

       Mole_Fraction Species {=} y0

       Progress_Variable ProgressVariableName {=} Value

       Real Data For Subroutine SubName {=} Values...

       Solid Object {=} t0

       Subroutine For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} SubName

       Subroutine For Mass_Fraction {=} Sub

       Subroutine For Mole_Fraction {=} Sub

       Update Enthalpy And Density

       Vof Shape For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} ShapeName ShapeArgs...

       Volume {=} Blocks...

    end Initial Condition Block BlockName

### 7.11.1.1. Line Commands

###### Primitivevariable

Syntax

  Primitivevariable {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} Value

Summary

  Assign initial condition to the specified variable. Specified value can be a constant or a string function of time, space, and global variables.

  The function string must be enclosed in quotes if it contains spaces or commas. For example: x_velocity = “min(1, 0.1*x + y)”

Parameter | Value | Default
--- | --- | ---
PrimitiveVariable | {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} | –
{=} | {= | are | is} | –
Value | “string” | –

###### Copy Nodal File Variable

Syntax

  Copy Nodal File Variable ExodusName To Region Field AfgoName [ At Time InterpTime ]

Summary

  Solid geometry to which this initial condition applies.

Parameter | Value | Default
--- | --- | ---
ExodusName | string | –
AfgoName | string | –

###### External Field For

Syntax

  External Field For VariableName {=} ExtFieldName [ Of Size Value ]

Summary

  Name of the field that is to be transferred in.

Parameter | Value | Default
--- | --- | ---
VariableName | string | –
{=} | {= | are | is} | –
ExtFieldName | string | –

###### External Field For Progress_Variable

Syntax

  External Field For Progress_Variable ProgressVariableName {=} ExtFieldName

Summary

  Name of the progress variable field that is to be transferred in.

Parameter | Value | Default
--- | --- | ---
ProgressVariableName | string | –
{=} | {= | are | is} | –
ExtFieldName | string | –

###### Function For

Syntax

  Function For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} FuncName In The {t | x | y | z} Direction

Summary

  Name of function with which to set the initial condition for the given variable in the given direction.

Parameter | Value | Default
--- | --- | ---
PrimitiveVariable | {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} | –
{=} | {= | are | is} | –
FuncName | string | –
Direction | {t | x | y | z} | –

###### Function For Mass_Fraction

Syntax

  Function For Mass_Fraction {=} FuncName In The {t | x | y | z} Direction

Summary

  Names of functions with which to set the initial mass fractions for the given species in the given direction.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
FuncName | string | –
Direction | {t | x | y | z} | –

###### Function For Mole_Fraction

Syntax

  Function For Mole_Fraction {=} FuncName In The {t | x | y | z} Direction

Summary

  Name of the mole fraction function to use for all species in the given direction. Note that this must be a Multicolumn function

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
FuncName | string | –
Direction | {t | x | y | z} | –

###### Ignite

Syntax

  Ignite

Summary

  Flag this block for combustion ignition

###### Inline Function For

Syntax

  Inline Function For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} FuncStr

Summary

  warning{This command is deprecated. Regular ICs now support using string functions directly}

Parameter | Value | Default
--- | --- | ---
PrimitiveVariable | {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} | –
{=} | {= | are | is} | –
FuncStr | “string” | –

###### Integer Data For Subroutine

Syntax

  Integer Data For Subroutine SubName {=} Values…

Summary

  List of integer data values to be passed down in to the user subroutine. These values may be changed by the user subroutine.

Parameter | Value | Default
--- | --- | ---
SubName | string | –
{=} | {= | are | is} | –
Values | integer… | –

###### Mass_Fraction

Syntax

  Mass_Fraction Species {=} y0

Summary

  Set the initial mass fraction. Specified value can be a constant or a string function of time, space, and global variables.

Parameter | Value | Default
--- | --- | ---
Species | string | –
{=} | {= | are | is} | –
y0 | “string” | –

###### Mole_Fraction

Syntax

  Mole_Fraction Species {=} y0

Summary

  Set the initial mole fractions to a constant value.

Parameter | Value | Default
--- | --- | ---
Species | string | –
{=} | {= | are | is} | –
y0 | “string” | –

###### Progress_Variable

Syntax

  Progress_Variable ProgressVariableName {=} Value

Summary

  Set the initial progress variable. Specified value can be a constant or a string function of time, space, and global variables.

Parameter | Value | Default
--- | --- | ---
ProgressVariableName | string | –
{=} | {= | are | is} | –
Value | “string” | –

###### Real Data For Subroutine

Syntax

  Real Data For Subroutine SubName {=} Values…

Summary

  List of real data values to be passed down in to the user subroutine. These values may be changed by the user subroutine.

Parameter | Value | Default
--- | --- | ---
SubName | string | –
{=} | {= | are | is} | –
Values | real… | –

###### Solid Object

Syntax

  Solid Object {=} t0

Summary

  Solid geometry to which this initial condition applies.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
t0 | string | –

###### Subroutine For

Syntax

  Subroutine For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} SubName

Summary

  Set the initial condition on the specified variable using a subroutine

Parameter | Value | Default
--- | --- | ---
PrimitiveVariable | {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} | –
{=} | {= | are | is} | –
SubName | string | –

###### Subroutine For Mass_Fraction

Syntax

  Subroutine For Mass_Fraction {=} Sub

Summary

  Set the initial mass fractions using a subroutine.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Sub | string | –

###### Subroutine For Mole_Fraction

Syntax

  Subroutine For Mole_Fraction {=} Sub

Summary

  Set the initial mole fractions using a subroutine.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Sub | string | –

###### Update Enthalpy And Density

Syntax

  Update Enthalpy And Density

Summary

  Flag this block for updating enthalpy after replacing T or Y

###### Vof Shape For

Syntax

  Vof Shape For {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} {=} ShapeName ShapeArgs…

Summary

  Set the smooth VOF initial conditions using basic shapes. Multiple shapes can be specified, and where they intersect will be a union operation.

Parameter | Value | Default
--- | --- | ---
PrimitiveVariable | {contact_angle | edc_product | gas_volume_fraction | mixture_fraction | pressure | progress_variable | scalar_variance | second_mixture_fraction | solid_volume_fraction | soot_mass_fraction | soot_nuclei_mass_fraction | temperature | turbulent_dissipation | turbulent_frequency | turbulent_helmholtz_function | turbulent_kinetic_energy | turbulent_v2 | volume_of_fluid | x_solid_velocity | x_velocity | y_solid_velocity | y_velocity | z_solid_velocity | z_velocity} | –
{=} | {= | are | is} | –
ShapeName | string | –
ShapeArgs | string… | –

###### Volume

Syntax

  Volume {=} Blocks…

Summary

  Element Block name(s) to which this initial condition applies.

  For multiple blocks, you can either use multiple VOLUME = X lines or specify all the blocks in one line as VOLUME = X Y Z.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Blocks | string… | –