1887

Abstract

The aim of this work is to explore the tremendous computer power of the new generation of workstations to model efficiently 3- D transient electromagnetic responses of complex conductive earth by finite element method. The transient solution is obtained via inverse cosine (sine) transform of the frequency domain solutions through very short digital filter integration. This takes about 20 frequency-domain solutions for each time-domain response. To minimize CPU time and memory (RAM and Disk) for each frequency-domain finite element solution, we use the preconditioned bi-conjugate gradient algorithm to solve the system of linear equations. With this technique, only the nonzero entries of the linear system are stored in the memory, a great benefit for such huge problem. It takes about 10 min for each frequency-domain solution for a fairly complex model energized by a grounded wire carrying a step function current. The complete transient response takes approximately 200 min. Comparison with known integral equation results shows that our algorithm is working properly. Cost-effective transient electromagnetic modelling is vital for electrical geophysical prospecting of conductive terrains in many parts of the world, in particular in the Amazon, Brazil.

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/content/papers/10.3997/2214-4609-pdb.324.1367
1993-11-07
2021-12-02
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http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609-pdb.324.1367
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