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B.3.6 Cells

Index: 12
Scheme symbol: xf-cell
C macro: XF_CELL
Status: required

The declaration section for cells is similar to that for nodes.

      (12 (zone-id first-index last-index type element-type))
Again, zone-id is zero to indicate that it is a declaration of the total number of cells. If last-index is zero, then there are no cells in the grid. This is useful when the file contains only a surface mesh to alert FLUENT that it cannot be used. In a declaration section, the type has a value of zero and the element-type is not present.

For example,

      (12 (0 1 3e3 0))
It states that there are 3e3 (hexadecimal) = 995 cells in the grid. This declaration section is required and must precede the regular cell sections. The element-type in a regular cell section header indicates the type of cells in the section, as follows:

element-type description nodes/cell faces/cell
0 mixed    
1 triangular 3 3
2 tetrahedral 4 4
3 quadrilateral 4 4
4 hexahedral 8 6
5 pyramid 5 5
6 wedge 6 5
7 polyhedral NN NF

where NN and NF will vary, depending on the specific polyhedral cell.

Regular cell sections have no body, but they have a header of the same format where first-index and last-index indicate the range for the particular zone, type indicates whether the cell zone is an active zone (solid or fluid), or inactive zone (currently only parent cells resulting from hanging node adaption). Active zones are represented with type=1, while inactive zones are represented with type=32.

In the earlier versions of FLUENT, a distinction was made used between solid and fluid zones. This is now determined by properties (i.e., material type).

A type of zero indicates a dead zone and will be skipped by FLUENT. If a zone is of mixed type ( element-type=0), it will have a body that lists the element-type of each cell. Example:

      (12 (9 1 3d 0 0)(
      1 1 1 3 3 1 1 3 1
Here, there are 3d (hexadecimal) = 61 cells in cell zone 9, of which the first 3 are triangles, the next 2 are quadrilaterals, and so on.

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