- distanceThe front is an infinite plane with normal pointing from start_posn to end_posn. The front's distance from start_posn is defined by distance. You should ensure that distance is positive
C++ Type:FunctionName

Description:The front is an infinite plane with normal pointing from start_posn to end_posn. The front's distance from start_posn is defined by distance. You should ensure that distance is positive

- end_posnFinal position of the front
C++ Type:libMesh::VectorValue

Description:Final position of the front

- start_posnInitial position of the front
C++ Type:libMesh::VectorValue

Description:Initial position of the front

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# MovingPlanarFront

The MovingPlanarFront has not been documented. The content contained on this page includes the basic documentation associated with a MooseObject; however, what is contained is ultimately determined by what is necessary to make the documentation clear for users.

This function defines the position of a moving front. The front is an infinite plane with normal pointing from start_posn to end_posn. The front's distance from start_posn is defined by 'distance', so if the 'distance' function is time dependent, the front's position will change with time. Roughly speaking, the function returns true_value for points lying in between start_posn and start_posn + distance. Precisely speaking, two planes are constructed, both with normal pointing from start_posn to end_posn. The first plane passes through start_posn; the second plane passes through end_posn. Given a point p and time t, this function returns false_value if ANY of the following are true: (a) t<activation_time; (b) t>=deactivation_time; (c) p is 'behind' start_posn (ie, p lies on one side of the start_posn plane and end_posn lies on the other side); (d) p is 'ahead' of the front (ie, p lies one one side of the front and start_posn lies on the other side); (e) the distance between p and the front is greater than active_length. Otherwise, the point is 'in the active zone' and the function returns true_value.

## Input Parameters

- active_length1.79769e+308Points greater than active_length behind the front will return false_value
Default:1.79769e+308

C++ Type:double

Description:Points greater than active_length behind the front will return false_value

- false_value0Return this value if a point is not in the active zone.
Default:0

C++ Type:double

Description:Return this value if a point is not in the active zone.

- activation_time-1.79769e+308This function will return false_value when t < activation_time
Default:-1.79769e+308

C++ Type:double

Description:This function will return false_value when t < activation_time

- true_value1Return this value if a point is in the active zone.
Default:1

C++ Type:double

Description:Return this value if a point is in the active zone.

- deactivation_time1.79769e+308This function will return false_value when t >= deactivation_time
Default:1.79769e+308

C++ Type:double

Description:This function will return false_value when t >= deactivation_time

### Optional Parameters

- 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.

- enableTrueSet the enabled status of the MooseObject.
Default:True

C++ Type:bool

Description:Set the enabled status of the MooseObject.

### Advanced Parameters

## Input Files

- modules/porous_flow/test/tests/functions/mpf_except1.i
- modules/porous_flow/test/tests/functions/mpf1.i