ADS interface to Pointwise
The Pointwise mesh generation software is a powerful tool for CFD analysis, so it is only logical to link its mesh generation capability to ADS CFD's Workbench and solver Code Leo. The interface between the software packages lies in two plugins to Pointwise:
- ADS/Leo (unstructured)
- ADS/Leo (structured)
This article is a guide to the process from getting started through to exporting a mesh from Pointwise to ADS format. It describes how to:
- Obtain and install the plugin if not in the Pointwise installation
- Select the solver and set conditions and solver attributes
- Export and initialization with ADS GEO
- Avoid Disaster/Troubleshoot
Obtain and install the plugin if not in the Pointwise installation
For Windows: C:\Program Files (x86)\Pointwise\Pointwise-
For Linux: place libCaeStr/UnsADS.dylib in '.../Pointwise/plugins/'
Restart Pointwise and verify that the plugin is found by going to 'CAE/Select Solver...' to find 'ADS/Leo (un)structured' in the list of available exporters.
Select the solver and set conditions and solver attributes
Once the desired mesh is ready for export to solver, go to 'CAE/Select Solver...' and select the appropriate 'ADS/Leo (un)structured' in the list of available exporters. The current exporter will be shown in the lower left corner of the Pointwise window. The requirements to export are:
- Set boundary conditions
- Set volume conditions
- Set solver attributes: title
Boundary condition assignment adds another degree of physics to the geometric model. Be very careful and aware of the conditions that are applied as this will have a direct affect on the solution. To set the boundary conditions, go to 'CAE/Set Boundary Conditions...' to open the boundary condition assignment table. Create new boundary conditions by selecting 'New' and adding the appropriate condition. Then, add faces to a condition by selecting a face and pressing the radio button on the left side of the row for the target condition in the condition table. The condition 'Name' field can be anything meaningful, but no spaces are allowed. The condition 'ID' should be unique for each condition and the value is not important with one exception: when using periodic boundary conditions (types 13/14 and 17/18), the corresponding faces must be linked with the condition ID; for example, a 13/14 pair would be have ID 3 and all other boundary conditions would have ID not 3. Each external face should have a boundary condition assigned to it or the default will be '0 No Condition' and this is an error.
For reference, that available boundary conditions are:
- 1 FLOW TANGENCY
- 2 UP-STREAM
- 3 DOWN-STREAM
- 4 FARFIELD IN/OUT
- 5 CASCADE UP-STREAM
- 6 CASCADE DOWN-STREAM
- 7 NO FLOW NORMAL TO THE SURFACE
- 8 WALL FUNCTION
- 9 NON-SLIP WALL WITH Q INPUT
- 10 NON-SLIP WALL Q = 0.0
- 11 NON-SLIP WALL IN STATIONARY FRAME
- 12 INLET FLOW NORMAL TO MESH
- 13 PERIODIC FACE
- 14 PERIODIC WITH FACE 13
- 15 CONSTANT T WALL FOR HEAT CONDUCTION
- 16 ADIABATIC WALL FOR HEAT CONDUCTION
- 17 INTERSECTOR PERIODIC WITH FACE
- 18 INTERSECTOR - PERIODIC WITH FACE 17
- 2008 WALL FUNCTION - CHT
The volume condition lets Code Leo know whether the problem type is fluid flow or heat conduction. To set the volume conditions, go to 'CAE/Set Volume Conditions...' to open the volume condition assignment table. Create new volume conditions by selecting 'New' and selecting 'fluid' or 'solid' from the drop down menu. Then, add volumes to a condition by selecting a domain and pressing the radio button on the left side of the row for the target condition in the condition table. The condition 'Name' field can be anything meaningful, but no spaces are allowed. The condition 'ID' should be unique for each condition and the value is not important.
Solver AttributesThe only solver attribute to set is the title for the mesh. This attribute is written inside of the exported mesh, it is not the file's name. To set the title, go to 'CAE/Set Solver Attributes...' to open the solver attributes window. In the 'Title' box, enter a string of less than 80 characters and spaces are allowed.
Export and initialize with ADS GEO
After setting the appropriate boundary conditions, volume conditions, and solver attributes, select the domains to export and go to 'File/Export/CAE...'. When the export window opens, select the location to save the files and a base name. The base name is what Leo will use in naming all result files, so be sure it is a meaningful and unique name.
On export, three files will be written:
The REST file contains the mesh, boundary, and volume conditions in binary ADS format. BCTYPE and BCVAL are only useful in unstructured meshing where they provide a boundary condition map for the ADS initialization. In structured meshing, BCTYPE and BCVAL will have 0 boundary conditions listed and will only contain header lines.
At this point, the exported .REST can be viewed in Paraview by converting with ads-vtk. The next step to Leo, however, is initialization with ads-geo. Initialization is completed easiest through the wizards in the ADS Workbench which help create the ads-geo input files and run the utility. This can be accessed from within the Workbench at 'File/Convert...'. Otherwise, see 'ADS Geo Reference.pdf' in the 'documentation' directory of your ADS installation for further information.
Avoid Disaster / Troubleshoot
Due to the nature of bringing a distinct mesher together with a solver, some possibilities exist for a mismatch in conventions. This sections deals with some more common but tricky problems and how to avoid them
IJK orientation for structured mesh
In turbomachinery applications, a particular i,j,k orientation is necessary for Leo to generate more useful output. The ADS convention is:
- Imin is the inlet face normal to axial, Imax is the outlet face normal to axial
- Jmin is the clockwise-most radial face , Jmax is the counter-clockwise-most radial face
- Kmin is the ID, Kmax is the OD