Control of Point Placement And Connectivity in Unstructured Grid Generation Procedures

IX International Conference on Finite Elements in Fluids: New Trends and Applications, Venice, Italy, October 15-21 1995

MESHING
RESEARCH
CORNER

NSF Engineering Research Center for Computational Field Simulation, Mechanical Engineering Department, Mississippi State University, USA, e-mail: marcum@erc.msstate.edu

Abstract
A procedure is presented for efficient generation of high-quality unstructured grids of triangular or tetrahedral elements for geometrically complex configurations. The overall procedure uses automatic point placement, direct insertion, and iterative local- reconnection. Field point spacing is derived from the boundaries through interpolation or from specified growth normal to the boundaries. Various procedures for point placement are implemented and compared. The procedures considered include, advancing- front, advancing-normal, circumcenter, and centroid point placement. Connectivity of the final grid is controlled by iterative local-reconnection subject to a connectivity quality criterion. Multiple quality criteria are implemented and compared. The criteria considered include, minimize maximum angle (min-max), minimize element skewness, and a Delaunay in-circle/sphere test. The various methods for point placement and connectivity control are compared for generation of triangular and tetrahedral elements. Results in both two- and three-dimensions indicate that advancing-front point placement with a min- max type connectivity criterion produces the highest quality grid.