A Comparison of two Parallelization Strategies for TRACE

In this report we compare two different methods of parallelization of a finite element code describing water flow in soils. The first method uses Domain Decomposition based on a parallel Schwarz algorithm. The second method uses a Data Partitioning approach pursued in High Performance Fortran (HPF). Experiments with the parallel versions were performed on the Paragon XP/S 10 at KFA

Numerische 3D-Simulation des Stofftransports in einem heterogenen Aquifer

The combination of field experiments and numerical simulation plays an important role in the characterization of the behaviour of dissolved substances in groundwater. Thousands of measurements have to be perfonned for many different parameters while numerical simulations need an extremely high number of computer resources. Here, mainly one aspect of the field experiments is presented, which deals with the measurement of the permeability. A flowrneter was used to achieve in situ results for several hundered locations. But the major part of this work deals with the development of an efficient software package which is able to simulate the movement of a solute plume in 3D with high resolution and with regard to its chemical behaviour. The program TRACE describes the water flow and is based on the finite element method and the Schwarz method which allows the parallelization of this software. PARTRACE simulates the solute movement in a given flow field and uses a particle tracking method. This method is ideal for parallelization and therefore no additional method is required. The software is able to deal with time dependent boundary conditions, saturated/unsaturated areas and - most important - with nonlinear chemical behaviour. Both programs are able to run on massively parallel computer systems like Intel Paragon or Cray T3E. Results for many different simulations are given. Both programs show good sCaling behaviour