Parametric Volume Models for Interactive Three-Dimensional Grid Generation

Abstract

Abstract A method based on non-uniform rational B-spline (NURBS) curve, surface, and solid technology is presented for interactive grid generation of three-dimensional flow fields encountered in turbomachinery applications. The method allows construction of several types of multi-block grids including H-, O-, and C-grids for two-dimensional grids, and strict H-grids for three-dimensional grid generation. Automated two-dimensional block construction is facilitated via a traversal method that searches four-sided regions in the initial block structure. A NURBS surface is then constructed on each block by transfinite interpolation of the boundary curves themselves, and various point distribution options may be applied. Three-dimensional grid generation is an extension of the two-dimensional procedure. Tri-parametric hyperpatches (NURBS solids) are constructed from the two-dimensional block surfaces and grids may be generated via several point distribution functions. This method exploits existing geometric design data via Initial Graphics Exchange Specification (IGES) input of NURBS-based component geometry. It provides an efficient and robust method for complex grid generation to support a variety of analysis functions. Several example applications are presented to demonstrate the capabilities of the technique.