- variableThe name of the variable that this residual object operates on
C++ Type:NonlinearVariableName
Controllable:No
Description:The name of the variable that this residual object operates on
NullScalarKernel
Scalar kernel that sets a zero residual, to avoid error from system missing this variable.
This kernel can be used as a placeholder if a nonlinear scalar variable was added to the simulation but the kernels for that variable have not yet been created / added to the input file. This kernel will ensure that the kernel coverage checking of the domain does not flag the variable as problematic. It will also ensure that the system matrix remains invertible as it contributes a small number times the identity matrix to the Jacobian for the variable it applies to.
Alternatives
Ideally, the non-linear scalar variable should be moved to be an auxiliary variable. This will reduce the size of the nonlinear system, making it easier to solve.
The kernel block coverage checking of the domain can also be turned off by setting
kernel_coverage_check=falsein the[Problem]block.A time derivative kernel can be used for a non-linear scalar variable with the missing physics kernels, as this describes a valid equation .
commentnote
This scalar kernel should mainly be used for creating small tests and while debugging simulations.
Input Parameters
- jacobian_fill0On diagonal Jacobian fill term, potentially needed for preconditioner
Default:0
C++ Type:double
Controllable:No
Description:On diagonal Jacobian fill term, potentially needed for preconditioner
Optional Parameters
- absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution
C++ Type:std::vector<TagName>
Controllable:No
Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution
- extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector<TagName>
Controllable:No
Description:The extra tags for the matrices this Kernel should fill
- extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector<TagName>
Controllable:No
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
Controllable:No
Description:The tag for the matrices this Kernel should fill
- vector_tagsnontimeThe tag for the vectors this Kernel should fill
Default:nontime
C++ Type:MultiMooseEnum
Controllable:No
Description:The tag for the vectors this Kernel should fill
Tagging Parameters
- control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
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
Controllable:Yes
Description:Set the enabled status of the MooseObject.
- implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Controllable:No
Description:Determines whether this object is calculated using an implicit or explicit form
- seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Controllable:No
Description:The seed for the master random number generator
- 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
Controllable:No
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.