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REGION

Defines a region (e.g. point, surface, volume) within the problem domain.

Required Cards:

REGION <string>

Opens the REGION block, where <string> is the name of the region.

Within the REGION block, one of:

COORDINATE <float float float>

Defines the x, y, z location of a single point in space (see note below)

COORDINATE x y z

COORDINATES

Defines two coordinates which define a box (see note below)

COORDINATES
  xmin ymin zmin
  xmax ymax zmax
/

BLOCK <int int int int int int>

Defines the i,j,k bounds of a region (structured grid only)

BLOCK istart iend jstart jend kstart kend

CARTESIAN_BOUNDARY <string>

Maps a boundary region to a Cartesian domain (structured grid only). The ‘FACE’ is implicit based on the string.

CARTESIAN_BOUNDARY [WEST, EAST, SOUTH, NORTH, BOTTOM, TOP]

FILE <string>

Non-boundary regions for all grid formats:

Specify a list of cell IDs in one of the following formats:

• ASCII: one cell ID per line

• HDF5 (.h5): cell IDs are in a 1D integer dataset named Regions/<region name>/Cell Ids.

STRUCTURED Grid:

Specify boundary faces through a list of cell and face IDs in one of the following formats:

• ASCII: one cell and face ID per line

• HDF5 (.h5): cell and face IDs are in two 1D integer datasets named Regions/<region name>/Cell Ids and Regions/<region name>/Face Ids, respectively.

Face IDs are numbered as: 1=west, 2=east, 3=south, 4=north, 5=bottom, 6=top.

UNSTRUCTURED Grid (Implicit):

Specify boundary faces through a list of vertex IDs in one of the following formats:

• ASCII (.ss): each line specifies a face element type (T=triangle and Q=quadrilateral) and associated vertex IDs

• HDF5 (.h5): 2D array of integers where the vertex IDs for each face are in the short dimension and the long dimension equals the number of faces.

UNSTRUCTURED_EXPLICIT Grid:

Specify boundary faces through a list of face connections in the following format:

• ASCII (.ex): one connection per line (cell ID, face center coordinate and face area).

Note that the suffixes .ss, .ex, and .h5 are reserved for the file formats defined above. See ASCII examples below or ASCII and HDF5 examples in PFLOTRAN_DIR/regression_tests/default/discretization.

POLYGON

Opens a block for defining a region by intersecting two polygons in separate XY, XZ or YZ planes.

LIST

A generic list of cell ids (not yet implemented).

Optional Card:

FACE <string>

Required when defining a surface (structured grid only).

FACE [WEST, EAST, SOUTH, NORTH, BOTTOM, TOP]

Examples

REGION source_zone
  FILE source_zone.h5
/

REGION all
  COORDINATES
    0.d0 0.d0 95.d0
    120.d0 120.d0 110.d0
  /
/

REGION West
  COORDINATES
    0.d0 0.d0 95.d0
    0.d0 120.d0 110.d0
  /
  FACE WEST
/

REGION East
  COORDINATES
    120.d0 0.d0 95.d0
    120.d0 120.d0 110.d0
  /
  FACE EAST
/

REGION South
  COORDINATES
    0.d0 0.d0 95.d0
    120.d0 0.d0 110.d0
  /
  FACE SOUTH
/

REGION South_Cartesian
  CARTESIAN_BOUNDARY SOUTH
/

REGION 2-9
  COORDINATE 60.07 88.75 102.5d0
/

REGION zone1
  BLOCK 45 90 32 40 1 100
/

REGION pond
  POLYGON
    TYPE BOUNDARY_FACES_IN_VOLUME
    XY
      1081.09 512.609 0.
      1008.38 536.404 0.
      957.98 554.706 0.
      ...
      860.4 401.267 0.
      950.316 432.744 0.
      1015.65 472.986 0.
    /
    XZ
      0. 0. 1.
      1126. 0. -22.
    /
  /
END

All Grids (non-boundary)

ASCII .txt format

1
2
...
N

STRUCTURED Grid

Boundary faces in ASCII .txt format

1 1   ! WEST face
2 4   ! SOUTH face
...
N 6   ! TOP face

UNSTRUCTURED Grid

Boundary faces in ASCII .ss format

4
Q 4 1 10 13
Q 7 4 13 16
Q 13 10 19 22
Q 16 13 22 25

EXPLICIT_UNSTRUCTURED Grid

Boundary faces in ASCII .ex format

CONNECTIONS 4
1 0. 0.5 0.5 1.
3 0. 1.5 0.5 1.
5 0. 0.5 1.5 1.
7 0. 1.5 1.5 1.

Note for COORDINATE/COORDINATES

If a region (point, line, or plane) lies between cells within a structured grid (i.e. at a face or corner between cells), it will be assigned to the upwind cell (lower I,J,K index). For instance, point X in

     |
  3  |  4
     |
-----X-----
     |
  1  |  2
     |

is assigned to cell 1, in

     |
  3  X  4
     |
-----|-----
     |
  1  |  2
     |

is assigned to cell 3, and in

     |
  3  |  4
     |
--X--|-----
     |
  1  |  2
     |

is assigned to cell 1.

A line or a plane is similarly assigned to the adjacent upwind cells. In the direction parallel to the line or plane, all cells INTERSECTED will be included (i.e. the region overlaps or crosses the boundary into the cell). For instance, line X in

     |
  3  |  4
     X
-----X-----
     X
  1  |  2
     |

will assign cells 1 and 3.

For 3D regions, the cells INTERSECTED by the volume will be included. If the boundaries of the region coincide with cell boundaries, only the encompassed cells are included. If there is ANY overlap of a 3D region with a cell (even femtometers into a cell), the cell is included. For instance, rectangle X in

     |
  3  |  4
   XXXX
---X-|X----
   XXXX
  1  |  2
     |

will assign cells 1, 2, 3 and 4, whereas

     |
  3  XXX4
     X X
-----XXX---
     |
  1  |  2
     |

only assigns cell 4.