Unstructured grid generation using iterative point insertion and local reconnection

Abstract

A procedure is presented for efficient generation of high-quality two- or three-dimensional unstructured grids of triangular or tetrahedral elements. The present procedure uses an iterative point creation and insertion scheme wherein points are created using advancing-front type point placement. Initially, the connectivity for these generated points is obtained by directly subdividing the elements which contain them, without regard to quality. This connectivity is then improved by iteratively using local reconnection subject to a quality criterion. For two dimensions, a min-max criterion is used and for three dimensions, a Delaunay in-sphere criterion followed by a min-max type criterion is used. The overall procedure is applied repetitively until a complete field grid is generated with a desired point distribution. Grid quality and performance statistics are presented for a variety of two- and three-dimensional configurations. The combined quality and efficiency attributes of this procedure appear to be a substantial improvement over existing methods.