Topology-based flow feature extraction on 3D vector fields

A 3D vector field flow topology extraction algorithm based on critical point analysis is presented for CFD (Computational Fluid Dynamics) data sets. It operates on curvilinear, structured grids, including large multi-zone grids. In many CFD computations, no-slip boundary conditions are imposed on the velocity field. On these boundaries, the fluid velocity vector is zero. The algorithm analyzes this special case by examining the skin friction field. Using glyphs to locate critical points, we can interactively mark vortex cores. This is drawn by selecting glyphs that indicate spiraling flow and integrating a streamline in the direction of the eigenvector associated with the real eigenvalue. The test results show clearly the fluid flow critical features.