BodyForce

Description

BodyForce implements a force term in momentum transport or structural mechanics or a source term in species/mass transport. The strong form, given a domain $var element = document.getElementById("moose-equation-567adc79-37c1-4b51-9a54-5fc36ad5c20a");katex.render("\\Omega", element, {displayMode:false,throwOnError:false});$ is defined as

$(1)var element = document.getElementById("moose-equation-cf77d1d4-b418-4160-9eae-3c50fa1a2245");katex.render("\\underbrace{-f}_{\\textrm{BodyForce}} + \\sum_{i=1}^n \\beta_i = 0 \\in \\Omega", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-f7dcd03e-ddad-4ddb-9ca6-fba279f66986");katex.render("f", element, {displayMode:false,throwOnError:false});$ is the source term (negative if a sink) and the second term on the left hand side represents the strong forms of other kernels. The BodyForce weak form, in inner-product notation, is defined as

$(2)var element = document.getElementById("moose-equation-f0d50403-ed86-4f36-9b22-9d35384b7e91");katex.render("R_i(u_h) = (\\psi_i, -f) \\quad \\forall \\psi_i,", element, {displayMode:true,throwOnError:false});$ where the $var element = document.getElementById("moose-equation-512d3051-7a5d-4402-b5fc-a74f9d7ca50a");katex.render("\\psi_i", element, {displayMode:false,throwOnError:false});$ are the test functions, and $var element = document.getElementById("moose-equation-e93eba50-b892-4ec8-9ca1-6228d1102798");katex.render("u_h", element, {displayMode:false,throwOnError:false});$ are the trial solutions in the finite dimensional space $var element = document.getElementById("moose-equation-ee484fb5-4559-419d-b8f1-f194eca2d138");katex.render("\\mathcal{S}^h", element, {displayMode:false,throwOnError:false});$ for the unknown ( $var element = document.getElementById("moose-equation-59ba8eb1-a720-4192-90ff-80539f06d442");katex.render("u", element, {displayMode:false,throwOnError:false});$ ).

The Jacobian term for this kernel is zero: $var element = document.getElementById("moose-equation-6d845a3b-88f4-4b56-bf0e-74636f9b6f97");katex.render("\\frac{\\partial R_i(u_h)}{\\partial u_j} = 0", element, {displayMode:false,throwOnError:false});$ , since it is assumed that $var element = document.getElementById("moose-equation-9b8cadac-787d-4543-8695-c3b6a32520d6");katex.render("f", element, {displayMode:false,throwOnError:false});$ is not** a function of the unknown $var element = document.getElementById("moose-equation-c607168f-8f0d-44da-9515-94bd4d536b2a");katex.render("u", element, {displayMode:false,throwOnError:false});$ .

The force is constructed through a user supplied constant $var element = document.getElementById("moose-equation-efbdc6af-d6fb-456c-b770-fb14a35694a2");katex.render("c", element, {displayMode:false,throwOnError:false});$ , function value evaluated at the current time and quadrature point $var element = document.getElementById("moose-equation-8f588cf8-2fdf-4412-97f4-315429bce80c");katex.render("f", element, {displayMode:false,throwOnError:false});$ , and/or postprocessor value $var element = document.getElementById("moose-equation-29c19d9a-fe39-4591-a8bf-3e34be9afe00");katex.render("p", element, {displayMode:false,throwOnError:false});$ . The constant $var element = document.getElementById("moose-equation-434e7d7c-9789-4bdc-a3e4-01aa9df11971");katex.render("c", element, {displayMode:false,throwOnError:false});$ , supplied through the parameter value, may also be controlled over the course of a transient simulation with a Controls block. $var element = document.getElementById("moose-equation-a6c0d6d6-4b36-4be7-9ca8-d57f0e851dc2");katex.render("c", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-98db579e-0bc0-4801-8fea-fc9e895ac701");katex.render("f", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-01a9edfb-2bc0-4c5c-9b2f-f05cb964552b");katex.render("p", element, {displayMode:false,throwOnError:false});$ are supplied through the input parameters value, function, and postprocessor respectively. Not supplying $var element = document.getElementById("moose-equation-60a440e1-d790-4f9d-a05d-301d5b621004");katex.render("c", element, {displayMode:false,throwOnError:false});$ , $var element = document.getElementById("moose-equation-7701d947-e083-4526-b4de-3f55aec048fe");katex.render("f", element, {displayMode:false,throwOnError:false});$ , or $var element = document.getElementById("moose-equation-b327bc5a-7241-44a6-9465-031d2baea8fe");katex.render("p", element, {displayMode:false,throwOnError:false});$ through its corresponding parameter is equivalent to setting its value to unity.

Example Syntax

The case below demonstrates the use of BodyForce where the force term is supplied solely through the constant value $var element = document.getElementById("moose-equation-2d3eb4dd-269a-429c-893c-abdf1a12d135");katex.render("c", element, {displayMode:false,throwOnError:false});$ (denoted by value):


[Kernels]
  active = 'bodyforce ie'

  [./bodyforce]
    type = BodyForce
    variable = u
    value = 10.0
  [../]

  [./ie]
    type = TimeDerivative
    variable = u
  [../]
[]

Input Parameters

variableThe name of the variable that this Kernel operates on
C++ Type:NonlinearVariableName
Description:The name of the variable that this Kernel operates on

Required Parameters

function1A function that describes the body force
Default:1
C++ Type:FunctionName
Description:A function that describes the body force
value1Coefficent to multiply by the body force term
Default:1
C++ Type:double
Description:Coefficent to multiply by the body force term
blockThe list of block ids (SubdomainID) that this object will be applied
C++ Type:std::vector
Description:The list of block ids (SubdomainID) that this object will be applied
postprocessor1A postprocessor whose value is multiplied by the body force
Default:1
C++ Type:PostprocessorName
Description:A postprocessor whose value is multiplied by the body force

Optional Parameters

enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Description:Set the enabled status of the MooseObject.
save_inThe name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Description:The name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Default:False
C++ Type:bool
Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
Description:Adds user-defined labels for accessing object parameters via control logic.
seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Description:The seed for the master random number generator
diag_save_inThe name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Description:The name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Description:Determines whether this object is calculated using an implicit or explicit form

Advanced Parameters

vector_tagsnontimeThe tag for the vectors this Kernel should fill
Default:nontime
C++ Type:MultiMooseEnum
Description:The tag for the vectors this Kernel should fill
extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector
Description:The extra tags for the vectors this Kernel should fill
matrix_tagssystemThe tag for the matrices this Kernel should fill
Default:system
C++ Type:MultiMooseEnum
Description:The tag for the matrices this Kernel should fill
extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector
Description:The extra tags for the matrices this Kernel should fill

Tagging Parameters

Description
Example Syntax
Input Parameters