# LevelSetOlssonReinitialization

This kernel implements the non-time portion of the conservative "re-initialization" algorithm of Olsson et al. (2007) that transforms into a smooth function in the range rather than a signed distance, which is useful for certain types of problems such as phase identification. The weak form of the re-initialization equation is: find such that

(1) where is the pseudo time during the re-initialization, is the normal vector computed from the level set variable at pseudo time , is the interface thickness, , and .

When steady-state for is detected when (see LevelSetOlssonTerminator the entire process is repeated at time .

## Example Syntax

The LevelSetOlssonReinitialization kernel is typically employed in a reinitialization sub-app (see the MOOSE MultiApp system), within this context this Kernel is invoked with the [Kernels] as follows.


[Kernels]
[./time]
type = TimeDerivative
variable = phi
[../]

[./reinit]
type = LevelSetOlssonReinitialization
variable = phi
phi_0 = phi_0
epsilon = 0.05
[../]
[]
(modules/level_set/test/tests/reinitialization/reinit.i)

## Input Parameters

• variableThe name of the variable that this Kernel operates on

C++ Type:NonlinearVariableName

Options:

Description:The name of the variable that this Kernel operates on

• epsilonThe epsilon coefficient to be used in the reinitialization calculation.

C++ Type:PostprocessorName

Options:

Description:The epsilon coefficient to be used in the reinitialization calculation.

• phi_0The level set variable to be reinitialized as signed distance function.

C++ Type:std::vector

Options:

Description:The level set variable to be reinitialized as signed distance function.

### Required Parameters

• blockThe list of block ids (SubdomainID) that this object will be applied

C++ Type:std::vector

Options:

Description:The list of block ids (SubdomainID) that this object will be applied

### Optional Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

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

Options:

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

Options:

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

Options:

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

Options:

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

Options:

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

Options:

Description:Determines whether this object is calculated using an implicit or explicit form

• vector_tagsnontimeThe tag for the vectors this Kernel should fill

Default:nontime

C++ Type:MultiMooseEnum

Options:nontime time

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

Options:

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

Options:nontime system

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

Options:

Description:The extra tags for the matrices this Kernel should fill

## References

1. Elin Olsson, Gunilla Kreiss, and Sara Zahedi. A conservative level set method for two phase flow ii. Journal of Computational Physics, 225(1):785–807, 2007. URL: http://dx.doi.org/10.1016/j.jcp.2006.12.027.[BibTeX]