The ICEM-CFD/NPARC interface writes an input file and a grid file for the NPARC flow solver version 3, from a 2D or 3D multiblocks structured grid created with MULCAD or with the HEXA-Mesher. This interface provides an option to automatically create the overlapps at block interfaces.
The NPARC input file controls how the NPARC program is executed. It contains the following sections:
The grid file is written in the multiblocks Plot3D format. The user has the option to write the grid file in single precision Fortran-unformatted (binary) or formatted.
For more information on NPARC, please refer to the NPARC Alliance Website.
In MULCAD, the block parameters must be defined on domains. After choosing a domain, select the menu item FLAG and enter the character string BLOCK. The remaining variables of the boundary conditions menu are used to specify the different block parameters for NPARC (see table below).
For grids generated with the HEXA-Mesher, the block parameters are defined on families. They should be applied to 2D-families for 2D models, and to 3D families for 3D models. After selecting a family, set the variable string1 to BLOCK, then use the remaining variables of the boundary conditions menu to specify the different block parameters for NPARC. The following table indicates which fields of the general boundary condition menu serve to define the NPARC block parameters.
_____________________________________________________________ MULCAD DDN-Mesher NPARC Type default parameter value _____________________________________________________________ 2. NR 3. integer invisc(1) integer 1 3. VALUE 4. real1 invisc(2) integer 1 4. X 5. real2 invisc(3) integer 1 5. Y 6. real3 lamin(1) integer 0 6. Z 7. real4 lamin(2) integer 0 7. SCALE 8. real5 lamin(3) integer 0 8. A 9. real6 cofmix real 0.09 9. B 10. real7 dtblk real 0.0 10. C 11. real8 gamma real 1.4 11. D 12. real9 dis2 real 0.25 12. ATTRIB 2. string2 dis4 real 0.64 _____________________________________________________________Note that for a 2D model, the parameters invisc(3) and lamin(3) are not written in the NPARC input file and therefore need not to be specified. The default values listed above are written for each block in the input file unless the block parameters are defined by the user. The value of dis4 is written in a character field (ATTRIB) and is limited to 5 characters.
In MULCAD, the boundary conditions must be defined on the edge entities for a bidimensional model and on the subfaces for a tridimensional model. After selecting a topological entity (edge or subface), define the boundary condition using the general boundary condition menu. The table below gives the correspondance between the variables in the MULCAD boundary condition menu and the NPARC variables.
For grids generated with the HEXA-Mesher, the boundary conditions are defined on edge-families for 2D models, or on face-families for 3D models. After selecting a family, define the NPARC variables in the general boundary condition menu. The following table indicates which fields of the general boundary condition menu serve to define the NPARC boundary condition parameters. Note that the translator creates by default a type 77 boundary segment at each undefined bloc interface.
For more details on how to set boundary conditions for the NPARC flow solver, please refer to the "NPARC User Manual".
_____________________________________________________________ MULCAD DDN-Mesher NPARC Type default variable value _____________________________________________________________ 2. NR 3. integer itype integer 0 4. X 5. real2 press real 0.0 5. Y 6. real3 temp real 0.0 6. Z 7. real4 edge integer 0 _____________________________________________________________By default, the boundary type is set to 70 on overlapped block interfaces, 77 on abutting block interfaces, 50 on walls (slip surface), and 81,82 or 83 on singularities.