hp submeshing via non-conforming finite element methods

Padmanabhan Seshaiyer and Manil Suri
Department of Mathematics and Statistics
University of Maryland Baltimore County
Baltimore, MD 21250, USA
padhu@math.umbc.edu, suri@math.umbc.edu


Non-conformity in the $hp$ version can involve incompatibility in both the degrees and the meshes between adjoining subdomains. In this paper, we show how the mortar finite element method M0 and two new variants M1, M2 can be used to join together such incompatible $hp$ sub-discretizations. Our results show optimality of the resulting non-conforming method for various $h, p$ and $hp$ discretizations, including the case of exponential $hp$ convergence over geometric meshes. We also present numerical results for the Lagrange multiplier when the method is implemented via a mixed method. Three-dimensional considerations suggest that our methods M1, M2 are easier to generalize to arbitrary meshes than M0.