A C0 interior penalty method for a singularly‐perturbed fourth‐order elliptic problem on a layer‐adapted mesh

We analyze the convergence of a continuous interior penalty (CIP) method for a singularly perturbed fourth-order elliptic problem on a layer-adapted mesh. On this anisotropic mesh, we prove under reasonable assumptions uniform convergence of almost order k − 1 for finite elements of degree k ≥ 2. This result is of better order than the known robust result on standard meshes. A by-product of our analysis is an analytic lower bound for the penalty of the symmetric CIP method. Finally, our convergence result is verified numerically. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 838–861, 2014