NONREFLECTING BOUNDARY CONDITIONS FOR TIME-DEPENDENT WAVE PROPAGATION
Event details
| Date | 13.10.2010 |
| Hour | 16:15 |
| Speaker | Dr. Imbo Sim |
| Location |
MAA110
|
| Category | Conferences - Seminars |
The constant demand for increasingly accurate, efficient, and robust numerical methods, which can handle acoustic, elastodynamic and electromagnetic wave propagations in unbouded domains, spurs the search for improvements in artificial boundary conditions. In the last decade, the perfectly matched layer (PML) approach has proved a flexible and accurate method for the simulation of waves in unbounded media. Standard PML formulations, however, usually require wave equations stated in their standard second-order form to be reformulated as firstorder systems, thereby introducing many additional unknowns. To circumvent this cumbersome and somewhat expensive step we propose instead a simple PML formulation directly in its second-order form in 3D. Our formulation requires fewer auxiliary unknowns than previous formulations. Starting from a high-order local nonreflecting boundary condition (NRBC) for single scattering, we derive a local NRBC for time-dependent multiple scattering problems, which is completely local both in space and time. To do so, we first develop a high order exterior evaluation formula for a purely outgoing wave field, given its values and those of certain auxiliary functions needed for the local NRBC on the artificial boundary. By combining that evaluation formula with the decomposition of the total scattered field into purely outgoing contributions, we obtain the first exact, completely local, NRBC for time-dependent multiple scattering. The accuracy, stability and efficiency of this new local NRBC is evaluated by coupling it to standard finite element or finite difference methods.
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Practical information
- General public
- Free
Contact
- Prof. Jacques Rappaz