Underneath the Overset: Other New Features in Pointwise V17.3
The marquee suite of new features in Pointwise Version 17.3 is its native coupling to overset grid assembly (OGA) tools. With these features you can use either PEGASUS or Suggar++ to compute the domain connectivity information for selected overlapping volume grids, both structured and unstructured. After integrating the connectivity information back into Pointwise, you will have diagnostics and visualizations to guide your mesh adjustments ensuring your grids have sufficient and proper overlap. This in turn ensures an accurate computational fluid dynamics (CFD) solution from your overset grid flow solver.
With such a large and powerful suite of features it might be easy to overlook that Pointwise V17.3 also contains many other new capabilities that will help you make all types of meshes better and faster.
T-Rex Hybrid Meshing
Those of you using T-Rex (anisotropic tetrahedral extrusion) to generate boundary-layer resolved hybrid meshes know that the method's implementation provides copious amounts of control to achieve exactly the mesh you want.
A new table (Figure 1) added to the top of the T-Rex attributes panel in the Solve command tallies information for all of the boundaries to which you have applied a Match boundary condition. This information provides guidance helping you consistently set similar attributes for the block in order to avoid skewed cells in the volume mesh.
Figure 1: The table of T-Rex match domain attributes helps you maintain consistency between your surface and volume meshes.
The Defaults panel (Figure 2) has been extended so you can now set default values for all T-Rex attributes. Because the method gives you control over many aspects of the meshing, the ability to set your preferred defaults is a time saver and ensures consistency.
Importing, Exporting, and Saving
New CAE Solver Support
In the CAE, Select Solver panel (Figure 3) you will find new support for four CFD file formats.
Updated Readers for CAD Files
Several of the CAD geometry readers in the File, Import, Database menu have been updated as follows.
Save Selection As
As you know, the Save command writes your entire mesh, geometry, and settings to a Pointwise native project file. But there are many times when it would be helpful to write just a few selected entities to a file. For example, you might want to share them with a colleague as the starting point for their new mesh. Now you can do this with the new File, Save Selection As command (Figure 4). This command automatically exports everything on which the selected entities depend (i.e. the parent entities). For example, selecting a domain will also result in its connectors and any associated database entities being saved too.
Saving and Reusing Your Environment
Building on the new Save Selection As command, would you like to be able to save everything except the mesh and geometry to a file? The project file saved by File, Save Environment (Figure 4) will contain everything you need to begin creating a new mesh just like the one you are currently working on including:
More PLOT3D Options
For structured grids in general, and structured overset grids in particular, the PLOT3D file format is the lingua franca. Therefore, a side benefit of the overset grid assembly feature suite is the extension of Pointwise's support for more of the PLOT3D files various attributes. In addition to previously supported attributes, Pointwise now supports
Multi-Body STL Support
Even though it is not part of the official STL file format standard, it is part of the de facto practical use of the format. Therefore, Pointwise's import and export support for STL, both ASCII and binary, has been extended to support multiple bodies in the file.
When exporting domains, their names are preserved in the file. When exporting blocks, the block name is used as a base name for naming all the faces.
User Interface Tools
Layer Manager Improvements
The layer manager (in the Layers panel, Figure 5) is a powerful tool for arranging and managing your grid and database entities for improved workflow and visual clarity. To make the tool a bit easier to use:
Figure 5: Assigning entities to layers just got a bit easier with relocation of the Assign Layer frame and selection highlighting in the Layers table.
Two relatively small changes to grid projection onto the database geometry can add up to some big time savings. First, database point entities can now be projected. This is handy for ensuring that geometry properly adheres to the CAD model.
Second, and probably more important, is the ability to project just a connector's shape, not its grid points. By way of background, keep in mind that a connector is defined by three components: its shape, its dimension (number of grid points), and its distribution function (how those grid points are arranged along the connector's length).
Previous versions of Pointwise assumed that when you projected a connector you also wanted each of its grid points projected in the same manner. The result was a connector consisting of a shape and distribution corresponding precisely to the projection of the original. To recover the distribution function, the variation of the projected grid points along the projected connector shape was splined and used thereafter as a distribution function of type “General.” While general distributions preserved the geometric act of projecting, they were “stiff” when you wanted to redistribute the grid points.
Therefore, the Project panel now includes a pair of radio buttons (Figure 6) so you can choose whether to project a connector's points (the old way) or only its shape (the new way). In the latter case, the connector's existing distribution attributes (function, spacing constraints) are simply reapplied to the projected shape. This means the points may move a little bit relative to where they were before projection but you will have a distribution that's easily adjustable.
Figure 6: The ability to project just a connector's shape avoids creating point distributions of the dreaded "general" type.
Normal Vector Display
You can now more easily comprehend and therefore edit the computational axis orientations of structured domains because the K axis (the one normal to the domain surface) is now displayed. This makes it much easier to see if any grids in a 2-D system are misaligned, which can cause problems in the flow solver.
For example, the computational orientations of the 2-D structured grid for a multi-element airfoil (Figure 7) appear to be properly aligned in the old 2-D view (Figure 8) but it can be hard to know for certain. The simple addition of the 3-D view including the K axis (Figure 9) reveals several misaligned domains when the domain is rotated. Look at the K vectors pointing to both the left and the right; they should all be pointing to the same side (i.e. outward pointing normal).
Generating a complex 3-D grid often involves creating equally complex mesh topology to ensure that zones connect properly, especially if your grids are multi-block structured hexahedra. When components are not aligned with the X, Y, or Z planes you often have to draw curves, for example, with nothing but your eyeball as a guide. This is where the Drawing Guide (in the Preferences menu, Figure 10) comes in handy. Using it you can create an array of screen-aligned horizontal and vertical lines (with density, color, and transparency that control) that provide a “graph paper” type effect that aids your drawing.
Try Pointwise for Yourself
So even if you are not generating overset grids, Pointwise Version 17.3 has many new tools to speed along your meshing work. To try it for yourself on your grids, request a free trial license today.