Hexahedra Unstructured Grid Generation For Viscous Flow Simulation

Numerical Grid Generation in Computational Field Simulations, The International Society of Grid Generation, pp.325-335, September 2000

MESHING
RESEARCH
CORNER

K. J. Verniers
Ch. Hirsch
Vrije Universiteit Brussel
Brussels, Belgium

Abstract

This paper presents a methodology to automatically generate high quality hexahedra unstructured mesh for complex geometries. A low quality, non-conformal and even non-manifold triangulation can be used to represent the geometry of the CAD model. The method does not rely on the generation of an initial high quality surface mesh. A volume grid with cell sizes compatible with the local length scales of the geometry is automatically generated by anisotropic subdivisions. The geometry is recovered by removing all cells which either intersect the geometry or are located outside of the computational domain. The remaining staircase volume mesh boundary is fitted to the geometryby a snapping procedure. Important geometry features such as corners and ridges are recovered. Mesh quality in the vicinity of the surface geometry is improved by adding buffers of hexahedral cells. Additional layers of high aspect ratio cells are created to allow the resolution of highly sheared flow regions. A final mesh optimization technique is applied to enhance the grid quality.