Abstract:
The solution of a second-order linear parabolic interface problem by the finite element method is
discussed. Quasi-uniform triangular elements are used for the spatial discretization while the time discretization is
based on a four-step implicit scheme. The integrals involved are evaluated by numerical quadrature, and it is assumed
that the mesh cannot be fitted to the interface. With low regularity assumption on the solution across the interface,
the stability of the method is established, and an almost optimal convergence rate of O
k
4 + h
2
1 + 1
| log h|
in the L2
(Ω)-norm is obtained. In terms of matrices arising in the scheme, we show that the scheme preserves the
maximum principle under certain conditions. Numerical experiments are presented to support the theoretical results.
