ANSYS ICEM CFD - Unigraphics Interface

FLOW-LOGIC Interface

Solver	FLOW-LOGIC
Type of mesh	multiblock and unstructured mesh
Dimension	2D and 3D

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Creating the FLOW-LOGIC file

The translator writes the FLOW-LOGIC file using the structured or unstructured mesh, the boundary condition file and the topology file. To create the FLOW-LOGIC files, "Select solver" → FLOW-LOGIC in the "Output" menu. . After clicking "Write input" you can specify options for the interface:

specify if the mesh is structured or unstructured
if structured domain(s), give the name of the boundary conditions file
if structured domain(s), give the name of the topology file
give the name of the output file

The interface generates the FLOW-LOGIC file located in the project directory.

Description of the FLOW-LOGIC File Format

The unstructured output consists of a node table followed by a connectivity table. The structured output is more complex, with information on the mesh topology and boundary conditions. The structured file content is explained in details in the following paragraphs.

Grid

The first part of the file contains the mesh coordinates in the PLOT3D file format.

nblocks
for each block: idim jdim kdim
for each block: all x, then all y, then all z

where:

nblocks: number of blocks in the mesh
idim, jdim, kdim: number of nodes in the i, j and k-directions.
x, y, z: node cartesian coordinates. Note that i is the fastest running index, then j, then k

Connectivity

This section describes the connectivity of each block with the rest of the grid. It contains a list of shared faces, edges and vertices.

conn_no block_no block_name orientation type beg1 beg2 beg3 end1 end2 end3
conn_no adjac_no adjac_name orientation type beg1 beg2 beg3 end1 end2 end3

where:

conn_no: connectivity number for this block
block_no: block number
block_name: name of domain file for this block
adjac_no: adjacent block number
adjac_name: domain file name for the adjacent block
orientation: index type {+ or -, i, j, or k} of directions 1, 2 and 3. For example, if the first direction corresponds to growing k indices, the second direction to decreasing i indices and the third direction to decreasing j indices, the orientation would be " k-i-j".
type: topological type; b=block, f=face, e=edge and v=vertex
beg1, beg2, beg3: starting indices in directions 1, 2 and 3
end1, end2, end3: ending indices in directions 1, 2 and 3

Boundary Conditions

This section list the boundary conditions associated with each block, surface, edge or vertice.

flag1 flag2 type imin jmin kmin imax jmax kmax

where:

flag1, flag2: character strings attached to the topological entity
type: topological type; b=block, f=face, e=edge and v=vertex
imin, jmin, kmin: minimum indices in the i, j and k-directions
imax, jmax, kmax: maximum indices in the i, j and k-directions

Defining boundary conditions on multiblock structured meshes (optional)

To define boundary condition click on the "BC" icon in the "Output" menu. Supported boundary conditions are:

Boundary condition	Value
BCname	enter a name, default is "BC_1"
BLock orientation	enter a string, default is "iXXX"

Imposing i-j-k orientation using the entity tagging (optional)

The orientation of each block can be set using the boundary condition tagging. This option is available only for the Flow-Logic structured output.

To reorient a block, 3 taggings are necessary, on the domain itself and on 2 of its edges. Select a domain icon and specify a unique flag of maximum 4 characters.

Then select the edges which will represent the i and j directions in the new orientation. The intersection of the 2 edges selected will be the new origin of the block (i=j=k=1).

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