USMKV3V Interface

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The ICEM/USMKV3V interface writes the grid and boundary condition information in the USMKV3V input file format. A maximum of 22 different mesh files can be generated for the following 22 different regions:

Creating the USMKV3V Input File

The translator writes the USMKV3V input files using structured domain files (domain.1 to domain.n), the boundary condition file (boco) and the topology file (topo_mulcad_out). The multi-blocks structured grid is first transformed into an unstructured grid file in the interface. This unstructured grid file is different from the one which would be created with the utility "structured -> Unstructured". The difference is that all 3D elements must be written as HEXA-8 with 8 distinct nodes even if they are degenerated. As a result, points on singularities are represented by more than one node. To create the USMKV3V input file, select the translator "USMKV3V" in the "Output" menu from the ICEM CFD/CAE Manager. After clicking "Write output" you can specify options for the USMKV3V interface: The interface generates the USMKV3V files located in the Transfer Shell. You may open a shell window in this directory by selecting the menu items "Utility" and "Transfer Shell".

Defining boundary conditions and properties for USMKV3V

For a grid generated with MULCAD/PADAMM, the "Unspecified Bound. Cond." menu in MULCAD is used to define vertex flags (FV), shell element groups and regions. For a grid generated with the HEXA-Mesher, the boundary conditions may be defined in the property menu of the DDN-Mesher-Interface, or directly from the HEXA-Mesher under the menu option "Edit boco". Please refer to the General Remarks section for more details. In P-Cube, the NAME and ZONE fields serve the same purpose. The settings required to correctly define boundary conditions and properties are described in the following sections.

Shell Elements:

In MULCAD, set FLAG to SHELL to indicate that the shell elements of a face need to be written in the grid file. In the DDN-Mesher interface set string1 to SHELL. In  HEXA-Mesher, select the Output/Bound conds menu in the mesh editor (MED). In P-CUBE, enter the word SHELL in the NAME field. The "shell" tagging is only recognized on surfaces.

        MULCAD          DDN-Mesher      P-CUBE
        ------          ----------      ------
        1.FLAG          1.string1       NAME field      Enter the word SHELL

Vertex Flag (FV):

In MULCAD, set FLAG to FV to indicate that a "Vertex flag" is being defined, then set NR to the vertex flag value (integer). In the DDN-Mesher interface set string1 to FV and integer to the vertex flag value. In  HEXA-Mesher, select the Output/Bound conds menu in the mesh editor (MED). In P-CUBE, enter the vertex flag under the ID # icon. The vertex flag (FV) can be assigned to either domains (blocks), subfaces (surfaces) or edges.

        MULCAD          DDN-Mesher      P-CUBE
        ------          ----------      ------
        1.FLAG          1.string1        -              Enter the string FV
        2.NR            3.integer       ID # icon       Enter the vertex flag number
Note that surface tagging overwrites block tagging and edge tagging overwrites surface tagging. The default value for FV is 999.
 

Parts:

The mesh should be divided in 2 parts: the cylinder and the ports. To specify in which of these 2 parts each 3D-mesh family or domain belongs, it must be tagged with one of the following keywords:

From MULCAD, enter the part keyword under the FLAG field of the Boundary Condition Menu. In the DDN-Mesher Interface set string1 to one of the keywords or in  HEXA-Mesher, select the Output/Bound conds menu in the mesh editor (MED). In P-CUBE, use the NAME field to specify the part tagging.
        MULCAD          DDN-Mesher      P-CUBE
        ------          ----------      ------
        1.FLAG          1.string1       NAME Field         Enter CYL, P1, ..., P20
Cell Flag (FC):

In MULCAD, set FLAG to FC to indicate that a "Cell flag" is being defined, then set NR to the cell flag value (integer). In the DDN-Mesher interface set string1 to FC and integer to the cell flag value. In th eHEXA-Mesher, select the Output/Bound conds menu in the mesh editor (MED). Cell flag is not supported for P-CUBE. The cell flag (FC) can be assigned to domains (blocks) only.

            MULCAD          DDN-Mesher
        ------          ----------
        1.FLAG          1.string1           Enter the string FC
        2.NR            3.integer           Enter the cell flag number

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