Particle Tracing in σ-Transformed Grids using Tetrahedral 6-Decomposition

Abstract

Particle tracing in curvilinear grids often employs decomposition of hexahedral cells into 5 tetrahedra. This method has shortcomings when applied to sigma-transformed grids, a grid type having strongly sheared cells, commonly used in hydrodynamic simulations. This paper describes an improved decomposition method into 6 tetrahedra. It is shown that this method is robust in sigma-transformed grids, however large the shear- ing. Results are presented of applying the technique to a real world sim- ulation. Comparisons are made between the accuracy and speed of the 5-decomposition and the 6-decomposition methods.