NEKTON Interface



This document describes the procedures to create the NEKTON Case and data file using ICEM CFD/CAE. The interface supports the following Grid Sections:

        Section                       Index
        -------                       -----
        Comment                          0
	Zones                           45
	Elements                       120
	Nodes                          130
	Surface Mesh                   140

Note: Surface geometry (section 110) is not supported by the interface.

Creating the NEKTON Input file

The translator writes the NEKTON input file using structured or unstructured domain files, the corresponding boundary condition file (boco or boco_info) and the topology file (topo_mulcad_out or topo_info). If structured domain files are selected, they are converted internally to an unstructured domain file prior to run the translator. To create the NEKTON input file, select the translator "NEKTON" in the "Output" menu from the ICEM CFD/CAE Manager. After clicking "Write input" you can specify the following options for the interface:

The interface generates the NEKTON file located in the Transfer directory. You may open a shell window in this directory by selecting the menu items "Utility" and "Transfer Shell".

Defining boundary conditions for NEKTON

In MULCAD the boundary conditions and properties are defined using the "Unspec. Bound. Cond." menu. For grids generated with the HEXA-Mesher, the boundary conditions and properties are defined in the "general bound. cond." menu of the DDN-Mesher Interface. Please refer to the General Remarks section for more details. The user can define the following NEKTON boundary conditions:

                     boco flag       domain    subface       edge
                                     (block)  (surface)

fluid                FLUID            3D        2D            -
periodic             PER              -         3D            2D
porous               POR              3D        2D            -
solid                SOLID            3D        2D            -
symmetry             SYM              -         3D            2D
velocity	     INLET or VELO    -         3D            2D
outflow		     OUT	      -         3D            2D
free surface         FREE             -         3D            2D
axis                 AXIS             -         3D            2D
wall                 WALL             -         3D            2D
traction             TRACT or OTHER   -         3D            2D
zone id              ZONE             3D        3D/2D         2D

For each boundary condition the user can define a zone-id. If no zone-id is entered, the translator generates a unique zone-id.

Boundary condition flag:

In MULCAD, the boundary condition flags are defined in the "Unspecified bound. cond." menu and in the DDN-Mesher Interface in the "general bound. cond." menu.

        MULCAD          DDN-Mesher
        ------          ----------
        1.FLAG          1.string1       Enter a bocoflag from the list above

In P-CUBE set the modal 'Analysis Code' to NEKTON then use the boundary condition icons (i.e. Outlet, Inlet, ...) to define NEKTON boundary conditions on blocks, faces or edges.

Zone identification number:

        MULCAD          DDN-Mesher      P-CUBE
        ------          ----------      ------
        1.FLAG          1.string1       n/a         Enter the string: ZONE
        2.NR            3.integer       ID# field   Enter the zone ID number

Details of limitations

The interface does not support Surface Geometry. It prints a default surface geometry section with no geometry data for all surface zones.