FunctionIC

An initial condition that uses a normal function of x, y, z to produce values (and optionally gradients) for a field variable.

Sets an initial condition via a Function described by parameter "function". It can be restricted to particular blocks and boundaries using the "block" and "boundary" parameters, respectively.

To set a function initial condition that preserves an integral of that function, such as for setting a volumetric quantity (units/m $var element = document.getElementById("moose-equation-0b842cdd-f0db-42e2-8714-9928edbfaaff");katex.render("^3", element, {displayMode:false,throwOnError:false});$ ) while satisfying a total volume-integral, see the IntegralPreservingFunctionIC.

Example input syntax

In this example, we set the initial value of variable u using a ParsedFunction. This particular example shows that information about the gradient of the parsed function is kept in initial condition, using further mesh refinement.

[ICs]
  [u_ic]
    type = FunctionIC
    variable = 'u'
    function = parsed_function
  []
[]

[Functions]
  [parsed_function]
    type = ParsedFunction
    expression = 'sin(x)-cos(y/2)'
  []
  [parsed_grad_function]
    type = ParsedGradFunction
    expression = 'sin(x)-cos(y/2)'
    grad_x = 'cos(x)'
    grad_y = 'sin(y/2)/2'
  []
  [parsed_zerograd_function]
    type = ParsedGradFunction
    expression = 'sin(x)-cos(y/2)'
    grad_x = '0'
    grad_y = '0'
  []
[]

Input Parameters

functionThe initial condition function.
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:The initial condition function.
variableThe variable this initial condition is supposed to provide values for.
C++ Type:VariableName
Unit:(no unit assumed)
Controllable:No
Description:The variable this initial condition is supposed to provide values for.

Required Parameters

blockThe list of blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Unit:(no unit assumed)
Controllable:No
Description:The list of blocks (ids or names) that this object will be applied
boundaryThe list of boundaries (ids or names) from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Unit:(no unit assumed)
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object applies
prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
scaling_factor1Scaling factor to apply on the function
Default:1
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Scaling factor to apply on the function
use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Default:False
C++ Type:bool
Unit:(no unit assumed)
Controllable:No
Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Unit:(no unit assumed)
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Unit:(no unit assumed)
Controllable:No
Description:Set the enabled status of the MooseObject.
ignore_uo_dependencyFalseWhen set to true, a UserObject retrieved by this IC will not be executed before the this IC
Default:False
C++ Type:bool
Unit:(no unit assumed)
Controllable:No
Description:When set to true, a UserObject retrieved by this IC will not be executed before the this IC

Advanced Parameters

(moose/test/tests/ics/function_ic/parsed_function.i)

#
# Test the automatically generated gradients in ParsedFunction and the gradient pass-through in FunctionIC
# OLD MOOSE behavior was for parsed_function to behave the same as parsed_zerograd_function
# NEW MOOSE behavior is for parsed_function to behave the same as parsed_grad_function
#

[Mesh]
  type = GeneratedMesh
  dim = 2
  xmin = 0
  xmax = 3.141
  ymin = 0
  ymax = 3.141
  nx = 10
  ny = 10
[]

[Variables]
  [u]
    order = THIRD
    family = HERMITE
  []
[]

[Functions]
  [parsed_function]
    type = ParsedFunction
    expression = 'sin(x)-cos(y/2)'
  []
  [parsed_grad_function]
    type = ParsedGradFunction
    expression = 'sin(x)-cos(y/2)'
    grad_x = 'cos(x)'
    grad_y = 'sin(y/2)/2'
  []
  [parsed_zerograd_function]
    type = ParsedGradFunction
    expression = 'sin(x)-cos(y/2)'
    grad_x = '0'
    grad_y = '0'
  []
[]

[ICs]
  [u_ic]
    type = FunctionIC
    variable = 'u'
    function = parsed_function
  []
[]

[Executioner]
  type = Steady
[]

[Problem]
  solve = false
[]

[Outputs]
  file_base = parsed
  [OverSampling]
    type = Exodus
    refinements = 3
  []
[]

Example input syntax
Input Parameters