a Multiple-Grid Evolution Scheme for 3-D Black Hole Excision
Abstract
When using black hole excision to numerically evolve a fully generic black hole spacetime, most 3-D 3 + 1 codes use an xyz-topology (spatial) grid. In such a grid, an r = constant excision surface must be approximated by an irregular and non-smooth "staircase-shaped" excision grid boundary, which may introduce numerical instabilities into the evolution. In this paper I describe an alternate scheme, which uses multiple grid patches, each with topology {r × (angular coordinates)}, to cover the slice outside the r = constant excision surface. The excision grid boundary is now smooth, so the evolution should be less prone to instabilities. With 4th order finite differencing, this code evolves Kerr initial data to 60M using the ADM equations; I'm currently implementing the BSSN equations in it in the hope that this will improve the stability.
- Publication:
-
The Ninth Marcel Grossmann Meeting
- Pub Date:
- December 2002
- DOI:
- 10.1142/9789812777386_0374
- Bibcode:
- 2002nmgm.meet.1743T