Boundary conditions block

The boundary condition block is composed of successive sublists, each defining a specific boundary. Each boundary sublist must contain the following entries:

  • Sideset ID: Name of the sideset. A list of sideset names may be provided if multiple sidesets share the same boundary condition.

  • Element Block ID: Name of the element block.

  • Strategy: Boundary strategy to be applied.

  • Data: Sublist containing the boundary values for each physics.

The boundary strategy is physics-dependent and therefore specific to each physics module or package. Within the core packages provided by Vertex-CFD, the following boundary strategies are available:

  • IncompressibleBoundaryFlux: incompressible Navier-Stokes equations, temperature equation, and induction-less MHD equation in a fluid domain.

  • ConductionBoundaryFlux: temperature equation in a solid domain.

  • SolidInductionLessMHDBoundaryFlux: induction-less MHD equation in a solid domain.

  • Multiphysics: combines multiple boundary strategies on a given solid/fluid domain.

The Multiphysics strategy allows boundary conditions from different physics modules to be combined within a single boundary block.

Note

In the current version of Vertex-CFD, the Multiphysics capability is only available for solid domains. Support for fluid domains is under development.

Listing 11 Boundary Conditions block in XML input file for different physics modules when assuming a geometry with N mesh blocks and M sidesets.
  <ParameterList name="Boundary Conditions">

    <ParameterList>
      <Parameter name="Sideset ID"        type="string" value="sideset_name_1, sideset_name_2"         />
      <Parameter name="Element Block ID"  type="string" value="block_name_1"  />
      <Parameter name="Strategy"          type="string" value="Multiphysics"/>
      <ParameterList name="Data">
        <ParameterList name="ConductionBoundaryFlux">
	  ......
	  [BOUNDARY DATA FOR CONDUCTION EQUATION IN SOLID DOMAIN]
	  ......
        </ParameterList> <!--ConductionBoundaryFlux-->
        <ParameterList name="SolidInductionLessMHDBoundaryFlux">
	  ......
	  [BOUNDARY DATA FOR INDUCTION-LESS MHD EQUATION IN SOLID DOMAIN]
	  ......
        </ParameterList> <!--SolidInductionLessMHDBoundaryFlux-->
      </ParameterList> <!--Data-->
    </ParameterList> <!-- -->

	  ...
	  ...
	  ...

    <ParameterList>
      <Parameter name="Sideset ID"        type="string" value="sideset_name_k"         />
      <Parameter name="Element Block ID"  type="string" value="block_name_k"  />
      <Parameter name="Strategy"          type="string" value="ConductionBoundaryFlux"/>
      <ParameterList name="Data">
	  ......
	  [BOUNDARY DATA FOR CONDUCTION EQUATION IN SOLID DOMAIN]
	  ......
      </ParameterList> <!--Data-->
    </ParameterList> <!-- -->

	  ...
	  ...
	  ...

    <ParameterList>
      <Parameter name="Sideset ID"        type="string" value="sideset_name_M"         />
      <Parameter name="Element Block ID"  type="string" value="block_name_N"  />
      <Parameter name="Strategy"          type="string" value="IncompressibleBoundaryFlux"/>
      <ParameterList name="Data">
	  ......
	  [BOUNDARY DATA FOR INCOMPRESSIBLE/TEMPERATURE/INDUCTION-LESS EQUATIONS IN FLUID DOMAIN]
	  ......
      </ParameterList> <!--Data-->
    </ParameterList> <!-- -->

  </ParameterList> <!--Boundary Conditions-->

The remaining of this section describes the content of the Data sublist, starting with BOUNDARY DATA … in the above listing.

Note

A bug was identified in the symmetry interior penalty (SIP) method implementation used for boundary flux of viscous/diffusion terms. The updated version of the SIP method can be enabled by setting Use Updated Penalty Parameter to true in the Data sublist block for each boundary condition. If not specified or set to false, the original version is used.

1      <ParameterList name="Data">
2        <Parameter name="Type" type="string" value="No-Slip"/>
3        <Parameter name="Use Updated Penalty Parameter" type="bool" value="true"/>
4        <Parameter name="Wall Temperature" type="double" value="305.0"/>
5      </ParameterList> <!-- Data -->