CFD-VisCART allows you to handle extremely complex geometries with lots of details. Often, you may have a geometry that you only modify slightly, but would like to use the mesh parameters that you used previously. In order to make this very simple, a batch mode was implemented for CFD-VisCART v2006.

Starting from an ASCII input file, you can import your geometry, set your mesh parameters and generate the mesh without ever opening the CFD-VisCART graphical interface. This obviously will decrease the time it takes to setup the mesh parameters for similar geometries, and while this situation may be the most obvious use, the batch mode option can be used for any case.

This user tip will show a short and simple example that can be extended to any complex geometry.

Example:

The input script lines along with their equivalent operations in the CFD-VisCART GUI are described below:

Import geometry
import_stl missile.stl 1

Equivalent in CFD-VisCART GUI: in the Import files panel, choose the STL File Type and select the missile.stl file.

Figure 1.  File → Import panel of CFD-VisCART

Manipulate geometry
rotateZ 1 30

Equivalent in CFD-VisCART GUI: In the GEOM tab, select Rotate for the Geometry Manipulation, select 'About Z-Axis' and provide the angle in degrees.

Figure 2.  Missle body after being rotated 30 degrees.

Setting Properties
set_bounding_box -100 -21 -21 125 50 21

Equivalent in CFD-VisCART GUI: In the Bounding Box Setting panel, provide Xmin, Xmax, Ymin, Ymax, Zmin and Zmax.

Sources
define_box_source 0 0 -10 45 25 10 2.0 1.0 1.0
define_surface_source 1 0.7 0.35

Equivalent in CFD-VisCART GUI: in the Source tab, select the box source, provide Min-Max corner Coordinates and Grid sizes. Select the missile surface in the Graphical window, select the surface source and provide normal and tangential length scales

Projected Mesh Generation: (______Single Domain Only______)
generate_projected_mesh omnitree 9.0 3.0 3.0 1.0 3 0.5 1.0

Equivalent in CFD-VisCART GUI: In the Projected Grid Generation panel, provide the Largest Cell Sizes in Simulation Area, number of Cartesian layers and Tangential and Normal directions cell sizes.

Projected Mesh Improvement
improve_mesh 5 10

Equivalent in CFD-VisCART GUI: In the Grid panel, provide the Min Angle and Max Iteration for the Detect/improve tool.

Save Results
save_vgd missile.VGD
save_dtf missile.DTF

Equivalent in CFD-VisCART GUI: Go to File → Save As VGD, and File → Save As DTF.

In order to use the batch mode capability, you must execute the command from an X-terminal, such as Exceed or startx that comes with Cygwin. In the X-terminal, simply type the following command to launch CFD-VisCART in batch mode:

Once it is done, your DTF file is ready to be loaded in CFD-ACE-GUI for the problem set up. Your VGD file is also ready to be read into CFD-VisCART for any modifications you may want to make. This new batch mode capability still has some limitations. For instance, it is not yet available for multiple domain mesh generation, but this additional capability could be available in a future version. If you would like to see a description of all the current functions available, please click here.

Regards,
Emmanuel Bot
Applications Engineer