toward automatic grid generation
DESCRIPTION
Toward Automatic Grid Generation. Si Loi Leung. University of Hawaii. Mechanical Engineering. Mentor: Dr. Nathan Prewitt. Project Goals. Write a program to generate shape structure graphs for any given boundaries - PowerPoint PPT PresentationTRANSCRIPT
Toward Automatic Grid Generation
Si Loi Leung
Mechanical Engineering
Mentor: Dr. Nathan Prewitt
University of Hawaii
Project Goals
• Write a program to generate shape structure graphs for any given boundaries
• Investigate how it could possibly be employed in automatic grid generation of any arbitrary boundaries
Outline
• How to create shape structure graphs
• Evaluation of the shape structure graphs
• A look at the medial axis
Grid Generation
Getting Complicated
Multi-Block Topology
Shape Structure Graphs
• Idea started from an article by Vitaly Ablavsky in the C/C++ Users Journal
Voronoi DiagramThe Voronoi diagram of a collection of nodes is a partition of space into cells, where any point within a cell is closer to its respective node than to any others.
Voronoi in Action
Medial AxisThe medial axis is the collection of center points of circles that touch the boundary at least twice.
Medial Axis in Action
Medial Axis in Action
Shape Structure Graph
The shape structure graph is a meta-graph with respect to the medial axis and retains only the “interesting” vertices.
Shape Structure Graph
Easymesh/Showmesh
Easymesh
• Bojan Niceno
• Generates two-dimensional unstructured meshes
• Showmesh is a graphical interface to show the results
Input
50: 0 0 5 11: 5 0 5 1 2: 5 2.5 5 2 3: 3.5 4 5 24: 0 4 5 1# x y scale marker
50: 0 1 11: 1 2 22: 2 3 33: 3 4 44: 4 0 5# a b marker
Output3
0: 0 3 4 -1 -1 1 5 6 4 2.5000 .25000 -1
1: 0 2 3 2 -1 0 4 2 1 2.4167 1.4167 -1
2: 3 1 2 -1 1 -1 3 1 0 1.7500 2.0000 -1
------------------------------------------------------------------------
e: i, j, k, ei, ej, ek, si, sj, sk xV, yV sign
samples
Evaluation
• Shape structure graph?
• Medial axis graph?
TopMaker
• By David L. Rigby, QSS Group
• Technique to generate multi-block topologies using the medial axis
How to Divide
Creating the Multi-block Topology
Something Like This
Conclusion
• Work in progress• What I learned
– C/C++
– Linux
– CFD
• Acknowledgement– Dr. Nathan Prewitt
– PET staff
– PET interns
Thank You