This section is referenced in the following other sections

- Simulation Setup: Non-Conformal

# 7.12.13. Nonconformal Boundary Condition On Surface

Scope

  Fuego Region

Summary

  Defines a non-conformal boundary condition on a named surface of the mesh.

    begin Nonconformal Boundary Condition On Surface Surfacename

        {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

       Enforce Zero Flux For Turbulence Wall Bc

       Normal Treatment {=} {keep_both | use_average | use_current}

       Omit Pressure Stabilization Term

       Opposing Sides {=} SideNames...

       Post Process Yplus

       Pressure Penalty Multiplier {=} PressurePenaltyMult

       Search Expansion Factor {=} SearchExpansion

       Search Method {=} {boost_rtree | kdtree}

       Search Tolerance {=} SearchTol

       Use Equilibrium Production Model

       Law_Of_Wall_Roughness_Parameter {=} Law of the Wall Roughness parameter

    end Nonconformal Boundary Condition On Surface Surfacename

## 7.12.13.1. 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

  Value for the specified variable (in consistent units). Value can be a constant or a string function of position (x,y,z), time (t), and any global variable.

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

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” | –

###### Enforce Zero Flux For Turbulence Wall Bc

Syntax

  Enforce Zero Flux For Turbulence Wall Bc

Summary

  warning{This command is deprecated and has no effect}

###### Normal Treatment

Syntax

  Normal Treatment {=} {keep_both | use_average | use_current}

Summary

  Select which search method to use. Options are USE_CURRENT (default), USE_AVERAGE, and KEEP_BOTH. You can specify this in just one non-conformal BC and it will apply to all. Specifying different treatments in different non-conformal BCs is currently not supported and will generate an error.

  In general, USE_CURRENT will provide the cleanest behavior, with the least amount of numerical noise at the interface. For very complex, moving and deforming geometries you may sometimes gain stability with the USE_AVERAGE treatment. KEEP_BOTH is generally not recommended, and is included for diagnostic purposes only.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
NormalMethod | {keep_both | use_average | use_current} | –

###### Omit Pressure Stabilization Term

Syntax

  Omit Pressure Stabilization Term

Summary

  Omits the pressure stabilization term at the non-conformal interface. This option can improve stability, particularly for difficult meshes, but may adversely affect convergence rates.

###### Opposing Sides

Syntax

  Opposing Sides {=} SideNames…

Summary

  List of opposing sides for non-conformal BC specification.

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

###### Post Process Yplus

Syntax

  Post Process Yplus

Summary

  Request post processing of yplus on this mesh part.

Description

  The normalized distance to the wall () can be post-processed on any wall (laminar or turbulent). Yplus is calculated in a manner consistent with how it is calculated in the solution procedure. Max/min values are provided as output at every wall. This option computes and stores the entire field along the wall. Since this option computes using the most recent values for all solution variables, the max/min written to the log may differ from the max/min of this field. However, these will become identical at convergence.

  Note that this line command does not automatically output this field to a results file. For that, one must use the standard output line command for a nodal field using the string name, `yplus`.

###### Pressure Penalty Multiplier

Syntax

  Pressure Penalty Multiplier {=} PressurePenaltyMult

Summary

  Multiplier to increase the penalty factor on discontinuous pressures at the non-conformal boundaries. Default = 1.0.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
PressurePenaltyMult | real | –

###### Search Expansion Factor

Syntax

  Search Expansion Factor {=} SearchExpansion

Summary

  Expansion factor for the search tolerance in terms of face size. Setting a value larger than 0 will expand the stencil so the linear system has to be re-initialized fewer times.

  Warning: This feature is under development and may incur a significant performance penalty at this time.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
SearchExpansion | real | –

###### Search Method

Syntax

  Search Method {=} {boost_rtree | kdtree}

Summary

  warning{This command is deprecated, KDTREE is the only supported option}

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
SearchMethod | {boost_rtree | kdtree} | –

###### Search Tolerance

Syntax

  Search Tolerance {=} SearchTol

Summary

  Search tolerance for the non-conformal side matching search. This is in real distance units and should be set larger than the expected gaps between sidesets due to faceting or geometry mismatches. If omitted, Fuego calculates this automatically as a tenth of the square root of the largest face area on the non-conformal BC.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
SearchTol | real | –

###### Use Equilibrium Production Model

Syntax

  Use Equilibrium Production Model

Summary

  Change near-wall turbulence production.

Description

  This option specifies that the near wall turb_ke production term is given by:

  . Modifications are made for the KW and SST model. This model is suggested when using the standard KW and SST model when a Dirichlet condition is not placed on the wall node of turbulence kinetic energy.

###### Law_Of_Wall_Roughness_Parameter

Syntax

  Law_Of_Wall_Roughness_Parameter {=} Law of the Wall Roughness parameter

Summary

  Specify dimensionless roughness factor to be used in the law-of-the-wall formulation.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Law of the Wall Roughness parameter | real | 9.8