In this paper, we use the eXtended Finite Element Method, with customized
enrichment functions determined by asymptotic analysis, to study boundary layer
behavior in elliptic equations with discontinuous coefficients. In particular, we look at
equations where the coefficients are discontinuous across a boundary internal to the
domain. We also show how to implement this method for Dirichlet conditions at an
interface. The method requires neither the mesh to conform to the internal boundary,
nor the mesh to have additional refinement near the interface, making this an ideal
method for moving interface type problems. We then apply this method
to equations for linearized biofilm growth to study the effects of biofilm
geometry on the availability of substrate and the effect of tip-splitting in biofilm
growth.
Keywords
X-FEM, extended finite element method, level set method,
elliptic equations, Helmholtz equation, biofilms