A grid connectivity file is needed for flow solves with DIABLO. The create_connect grid utility is used to automatically create the connectivity file. The file extension for the grid connectivity file is .con. Below is an example of a grid connectivity file for a 2D single block grid:

Block connectivity file for Diablo
number of blocks
1
number of subfaces
7
number of interfaces
1
___
| face | type | blk | side | it1 | it1begin | it1num | it2 | it2begin | it2num |
....1........2......1......1.... 2.........1...........1....... 3.......1...........65
....2........2......1......2.....2.........1...........1........3.......1...........65
....3........2......1......6......1........1.........281.......2......1............1
....4........3......1......3.....1.........1.........281.......3.......1..........65
....5........0......1......5....-1.........41.......41.........2.......1...........1
......................1.......5.....1........241......41.........2.......1...........1
....6........3......1.......4.....1........1........281........3........1..........65
....7........1......1.......5.....1........41......201........2........1..........1

IT1, IT2: Tangential directions wrt to block faces. Each block face has 1 normal direction and 2 tangential directions.

Node indexes j,k,m correspond to cartesian coordinate directions x,y,z. In the connectivity file, numerical values 1,2,3 correspond to the node indexes j,k,m. For example, on block face 1, its two tangential directions, it1 and it2 are 2 and 3 respectively. This means that k and m are tangential directions for block face 1.

Explanatory Notes

Face Type (see Partition_Mod.f90 in ~/jetstream/diablo/)
0 - Interface
1 - Solid Wall (generic aerodynamic surface)
2 - Far field
3 - Symmetry Plane
4 - Dirichlet Boundary Conditions based on far field
5 - Collapsed Side Boundary
6 - Viscous Outflow
7 - Fully Extrapolated Outflow
8 - Far field with Abzone
101 - Wing surface
102 - Tail surface
103 - Fuselage surface

To help visualize the block structure see pages 4 and 5 of the Diablo Developer's Guide.