Finite Element Method with Transparent Boundary Condition
To handle unbounded computational domains, we introduce Dirichlet-to-Neumann map (DtN) which maps the Dirichlet value to the Neumann value of the solution of a boundary value problem. In our problem, we construct the DtN map based on the Rayleigh expansion radiation conditon. Then the DtN map give rise to a transparent boundary conditon on the artificial boundary which truncates the unbounded domain.