7.16.2.1. Initial Condition

Scope: Aria Region
Summary: Allows the specification of a user-defined initial conditions on any combination of volumes, surfaces and nodes.
Description: There are three methods for setting the initial conditions of the thermal model. The temperature specification must be of exactly one type: e.g., constant, defined in a user subroutine, or read from a solution database file. If a user subroutine is used, real and integer data may be declared that will be local in scope to this instance of the boundary condition. This data may be accessed using a user query function.

begin Initial Condition BlockName

   Add Surface PartList...

   Add Volume PartList...

   All Volumes

   Node Subroutine {=} Name

   Temperature {=} t0

   Use Data Block Name

   Use File Variable File_variable_name For Aria_variable_name ([{of} SpeciesName]  | [{in} MaterialPhaseName]) [ At Time Value  ]

end Initial Condition BlockName

7.16.2.1.1. Line Commands

Add Surface

Syntax: Add Surface PartList…
Summary: Surface name to which this initial condition applies. May specify a space-delimited list.

Parameter	Value	Default
PartList	string…	–

Add Volume

Syntax: Add Volume PartList…
Summary: Block names to which this initial condition applies. May specify a space-delimited list.

Parameter	Value	Default
PartList	string…	–

All Volumes

Syntax: All Volumes
Summary: Apply this command block to all volumes in the mesh file.

Node Subroutine

Syntax: Node Subroutine {=} Name
Summary: Specifies that the named user-defined subroutine be used. At most one subroutine name may be specified for a given quantity. This subroutine must conform to the “node signature” argument list type.

Parameter	Value	Default
{=}	{= \| are \| is}	–
Name	string	–

Temperature

Syntax: Temperature {=} t0
Summary: Set the initial temperature to a constant value.

Parameter	Value	Default
{=}	{= \| are \| is}	–
t0	real	–

Use Data Block

Syntax: Use Data Block Name
Summary: Reference to predefined data to be used by the user subroutine. These values may be changed by the user subroutine.

Parameter	Value	Default
Name	string	–

Use File Variable

Syntax

Use File Variable File_variable_name For Aria_variable_name ([{of} SpeciesName] | [{in} MaterialPhaseName]) [ At Time Value ]

Summary

Assign file nodal variable to valid registered nodal variable for initial condition.

Description

This line command specifies that the named Aria variable be initialized from a variable contained in the mesh file that is assigned to the region. For example, this line command may be used to initialize a transient calculation from a previously performed steady-state calculation in the following way. Perform the steady-state calculation and output the temperature. Then copy that output file and use it as a mesh file for the transient calculation. Finally, use this line command to tie the variable named file_variable_name in the mesh file to the aria variable named aria_variable_name. Here aria_variable_name must be set to nonlinear_solution->temperature.

The closest time step to the time value found the IO database will be used for the assignment. For an initial condition taken from a steady state results file, omit the optional time command. The optional command is necessary if the initial condition is coming from a file with multiple timesteps.

Note

Current framework services do not allow restricting this initialization by mesh subset. e.g., if you want to initialize the temperature, then all nodes in the mesh will be initialized.
This command line syntax only supports initialization of temperature field. This restriction may be removed in the future so that chemistry variables or user-defined variables may also be initialized.
Sierra Mechanics uses a DOF naming convention which distinguishes vector fields from scalar fields using an underscore plus component notation (e.g. field_variable_base_name_1, field_variable_base_name_X). Hence use of external scalar field variable names that include an indexed notation will require that the file variable be renamed in order to be processed correctly as a scalar field in the IC READ_FILE setup.

Parameter	Value	Default
File_variable_name	string	–
Aria_variable_name	string	–
{of}	{of \| species}	–
SpeciesName	string	–
{in}	{in \| material_phase}	–
MaterialPhaseName	string	–