Collection of abstracts 14th GAMM-Seminar Kiel on Concepts of Numerical Software January 23rd to 25th, 1998.

Saturday, January 24th, 1998

Efficient hierarchical Searching on arbitrary nested Grids,
Application to Particle Tracing

Post processing in computational fluid dynamics requires efficient visualization on unstructured, hierarchical and often economical stored grids. Particle methods which generate and visualize particle lines, stream surfaces, or moving clouds of particles are important tools for the examination of velocity fields. The efficiency of these methods depends sensitively on searching algorithms. Especially for economically stored, very large data sets the storing of adjacency information is ruled out. For hierarchical meshes consisting of elements which are cartesian products of simplices and recursively generated applying a finite set of refinement rules, a method for hierarchical searching is presented. In terms of computational effort this strategy is almost optimal. It is based on optimal mapping of local coordinates and local searching in the hierarchical tree of data. For the above class of grids a unique interface is implemented. Illustration examples demonstrate the applicability for a variety of particle tracing methods.