Evanescent waves in PML's: origin of the numerical reflection in wave-structure interaction problems

摘要

The theory of general evanescent waves in perfectly matched layers (PMLs) is presented, both in a continuous medium and in a discretized finite-difference medium. It is shown that evanescent waves may be strongly reflected from vacuum-PML interfaces in the discretized case. This allows the numerical reflection observed in wave-structure interaction problems to be interpreted as the reflection of evanescent fields surrounding the structures.