7.11. Initial Temperature

BEGIN INITIAL TEMPERATURE
  #
  # block set commands
  INCLUDE ALL BLOCKS
  BLOCK = <string list>block_names
  ASSEMBLY = <string list>assembly_names
  REMOVE BLOCK = <string list>block_names
  ELEMENT = <int_list>elem_ids

  NODE SET|NODESET = <string list>nodeset_names
  REMOVE NODE SET = <string list>nodeset_names
  NODE = <int_list>node_ids
  #
  # specification command
  MAGNITUDE = <real>initial_temperature_value
  #
  # user subroutine commands
  NODE SET SUBROUTINE = <string>subroutine_name
  SUBROUTINE DEBUGGING OFF | SUBROUTINE DEBUGGING ON
  SUBROUTINE REAL PARAMETER: <string>param_name
    = <real>param_value
  SUBROUTINE INTEGER PARAMETER: <string>param_name
    = <integer>param_value
  SUBROUTINE STRING PARAMETER: <string>param_name
  #
  # external database commands
  READ VARIABLE = <string>var_name
  COPY VARIABLE = <string>var_name [FROM MODEL <string>model_name]
    MAP_BY_PROXIMITY|MAP_BY_ID(MAP_BY_PROXIMITY)
  TIME = <real>time|FIRST|LAST
END [INITIAL TEMPERATURE]

The INITIAL TEMPERATURE command block initializes a temperature field on the prescribed mesh entities. The temperature field is set on a nodal field temperature and interpolated to the integration points of an element field temperature.

The temperature field may evolve later through interaction with material models that support temperature evolution features such as adiabatic heating. In this case, only the element temperature field is changed and will become out-of-sync with the nodal temperature field.

The simplest example for initializing temperature is as follows:

begin initial temperature
    include all blocks
    magnitude = 294.0
end

The initial temperature block may appear multiple times. In the case where temperature has already been prescribed on one node (e.g. two merged blocks with different temperatures), the last initial temperature specification wins.

A PRESCRIBED TEMPERATURE command block may exist within the same scope as an INITIAL TEMPERATURE command block. It is possible that the prescribed temperature at the initial analysis time conflicts with what is specified in the INITIAL TEMPERATURE block. In this case, the PRESCRIBED TEMPERATURE block wins and will subsequently provide a temperature at every time step.

7.11.1. Block Set Commands

The block set commands portion of the INITIAL TEMPERATURE command block defines a set of nodes associated with the prescribed temperature field and can include some combination of the following command lines:

BLOCK = <string list>block_names
ASSEMBLY = <string list>assembly_names
INCLUDE ALL BLOCKS
REMOVE BLOCK = <string list>block_names
ELEMENT = <int_list>elem_ids
NODE SET|NODESET = <string list>nodeset_names
REMOVE NODE SET = <string list>nodeset_names
NODE = <int_list>node_ids

These command lines, taken collectively, constitute a set of Boolean operators for constructing a set of nodes derived from some combination of element blocks. See Section 7.1.1 for more information about the use of these command lines for creating a set of nodes used by the boundary condition. There must be at least one BLOCK, INCLUDE ALL BLOCKS, ELEMENT, ASSEMBLY, NODE SET|NODESET, or NODE command line in the command block. Assemblies may contain blocks, nodesets, or assemblies of these.

7.11.2. Specification Commands

The MAGNITUDE command may be used to specify a constant temperature for the selected mesh entities.

The initial temperature field may also vary over space by using either the user subroutine commands, or the external mesh database commands. For example, the exodus results database of a SIERRA/TF analysis may be used to initialize a Sierra/SM analysis. The usage details for this follow directly from the description in Section 7.12.