I’m Rajib Roy and this May I joined Pointwise as a summer intern on the Sales & Marketing team.  During my first week I generated an unstructured viscous boundary layer mesh for a glider geometry. I used the 3D anisotropic tetrahedral extrusion (also known as T-Rex) method to generate a high-quality, hex-dominant boundary layer extrusion and far field mesh.

Since volume mesh quality depends on the underlying surface mesh, my key meshing focus was to produce a surface mesh that adequately represents the complex geometry of the glider. In order to resolve regions of high curvature (e.g. leading and trailing edges of the wing), 2D T-Rex was used to generate anisotropic triangles which reduced the surface-cell count significantly compared to pure isotropic triangle refinement.

When using 2D T-Rex, connectors designated as “match” type boundary conditions receive a growth distribution that is defined by an initial spacing and growth rate. Therefore, curvature based refinement (e.g. turning angle or surface deviation) is not automatically enforced. To properly resolve the curvature for this project, I wanted to specify an initial spacing for 2D T-Rex that resulted in a lower turning angle between adjacent facets. Using Glyph, I wrote a utility to compute the turning angle between adjacent grid points along connectors so that I could more appropriately define my grid spacing. Moreover, the script can also calculate maximum and minimum turning angles for a group of selected connectors which is helpful when examining the overall grid tuning angle quality metric.

Upon executing the script, a Tk interface opens and prompts the user to choose from two interactive modes. The first mode is “Select Point” which prompts the user to select any connector grid point and calculates the corresponding turning angle. The second mode is “Select Connectors” which prompts user to select a group of connectors and provides the maximum and minimum turning angles for each of the connectors selected. These two modes can be switched and recalled as many times as necessary.

To download this script directly, you can use this link. If you would like to visit the repository on GitHub, then please visit https://github.com/pointwise/TurningAngleCalculator.

If you have an idea for a new Glyph script, and you would like to learn more about how to get started, then contact us via the comments section below or contact @Pointwise on Twitter. We’re also interested in learning more about the Glyph scripts our users have created. Get in touch with us if you would like to share and have your script highlighted here on Another Fine Mesh.