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 ( $y^+$ ) 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 $y^+$ values are provided as output at every wall. This option computes and stores the entire $y^+$ field along the wall. Since this option computes $y^+$ 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:

$\frac{{\tau_w}^2}{\kappa \sqrt[4]{C_\mu}\rho y_p \sqrt{k}}$

. 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