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Recent Development and Applications of the EPOGS Toolset for Automatic Structured Overset Mesh Generation

AMS Seminar Series

Speaker: William M. Chan, Computational Aerosciences Branch, NASA Ames Research Center

Presentation

Seminar Slide Deck (PDF-11.7MB)

Abstract

Automation of overset structured surface mesh generation has recently been accomplished by the creation of face, edge, and node meshes based on Boundary Representation (BREP) solids as the geometry input. Recent developments in the automation of volume mesh generation and domain connectivity from the resulting surface grids are presented. Near-body hyperbolic curvilinear volume grids are created with automated selection of surface grid point distribution and automated sequencing of smoothing parameters at difficult concave junctions. Volume mesh overlap quality is enhanced by the introduction of a new automatic boundary splay adjustment scheme. Hole-cutting between near-body volume grids is guided by distance functions along grid strands in the normal direction from the wall, while a direct ray-piercing test is used to cut holes in the off-body Cartesian grids.

Recent testing of the overset mesh generation automation software toolset EPOGS on several applications are presented. These include various VTOL concept vehicles from the Revolutionary Vertical Lift Technology (RVLT) project, mesh families for multiple CRM configurations from the AIAA Drag Prediction Workshop 8 (DPW8), and component increment and positioning studies for the Tiltwing Test Rig (TWTR) wind tunnel experiment. The current meshing process involves running EPOGS followed by minor grid repairs where needed. Significant reductions in meshing turn-around time have been demonstrated using this procedure compared to a completely manual approach.

This work has been supported by NASA’s Revolutionary Vertical Lift Technology (RVLT) and Transformational Tools and Technologies (T3) projects.

Biography

Photo of William M. Chan
William M. Chan is a Computer Scientist at the Computational Aerosciences Branch at NASA Ames Research Center. His work involves algorithm and software development for grid generation, pre-processing, and post-processing for overset grid CFD analysis applied to complex configurations. He is the principal developer of the Chimera Grid Tools software package that has been distributed to over 1200 U.S. organizations via the NASA Software Usage Agreement. Applications that he has supported include a variety of subsonic transport, vertical-lift, and space launch vehicles, as well as various turbopumps and liquid rocket sub-systems. He obtained his B.S. in Mathematics from Southampton University, U.K., and M.S. and Ph.D. from the Mechanical Engineering Department at Stanford University. William is an Associate Fellow of AIAA.