Uniform Regions

As its name implies, the UniformRegion object defines a region where the hydrodynamic variables are constant. The region itself is defined by a Shape object passed in when the UniformRegion is created. The UniformRegion can be used as a one-shot or it can be made persistent, in which case it would be renewed before every step (i.e., by a subroutine called in beforeStep()).

Object Definitions

UniformRegion:

TYPE(ShapeDef), POINTER :: Shape
REAL(KIND=qPREC), DIMENSION(:), ALLOCATABLE :: q
INTEGER :: SubSample = 1
LOGICAL :: PersistInBoundaries = .false.
LOGICAL :: PersistInternal = .false.

• *Shape: A pointer to a Shape object that defines the dimensions of the region this object will keep uniform.

• q: A state vector containing the hydrodynamic variable values this object will enforce within the uniform region.

• SubSample: An integer value used to determine the sub-sampling resolution. The default value for SubSample is 1.

• PersistInBoundaries: Indicates whether the uniform region is persistent. Under this option, beforeStep() only enforces the uniform region up to a grid's physical boundaries. By default, this option is turned off.

• PersistInternal: Indicates whether the uniform region is persistent. Under this option, beforeStep() will enforce the uniform region within a grid's ghost regions as well. By default, this option is turned off.

How to Use this Object

The uniform regions object contains a ShapeObject that defines where the uniform value q is to be applied. The SubSample defines how many sub cells in each direction are sampled. If PersistInBoundaries is true then anywhere the object overlaps with physical boundaries - the values are maintained during the simulation. If PersistInternal is true then the values are maintained wherever the object exists.

SUBROUTINE ProblemModuleInit()
  TYPE(UniformRegionDef), POINTER :: UniformRegion 
  CALL CreateUniformRegion(UniformRegion) 
  UniformRegion%q(1:NrHydroVars)=qout(1:NrHydroVars)
  UniformRegion%q(1)=density
  CALL SetShapeType(UniformRegion%Shape, CIRCLE, radius)
  CALL SetShapeOrientation(UniformRegion%Shape, psi, theta, phi)
  SplitRegion%Shape%Position=position
  CALL SetShapeBounds(UniformRegion%Shape)
END SUBROUTINE ProblemModuleInit

When you call CreateUniformRegion it adds the uniform region to a list and then automatically handles the initialization and the necessary boundary conditions. There is nothing else you have to do.