Generation of Unstructured Grids for Viscous Flow Applications

33rd Aerospace Sciences Meeting and Exhibit, Reno, NV., AIAA 95-0212, January 9-12 1995

MESHING
RESEARCH
CORNER

David L. Marcum: 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 suitable for viscous flow applications. The present procedure uses an iterative point creation and insertion scheme wherein points are created using either advancing- front type or advancing-normal type point placement. Advancing-normal point placement is used to generate high aspect ratio elements. Initially, the connectivity for these generated points is obtained by directly subdividing the element which contains 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. In two-dimensions, triangular elements in the viscous regions are optionally combined to form quadrilateral elements. Results are presented for a variety of two-dimensional configurations. Preliminary results are also presented for extension of the present viscous grid generation methodology to three- dimensions. 'Me results demonstrate that high quality unstructured grids suitable for inviscid or viscous flow applications can be generated about geometrically complex configurations.