Continuous Linear Finite Element Method for Biharmonic Problems on Surfaces
Ying Cai, Hailong Guo, Zhimin Zhang
TL;DR
This work develops a $C^0$ continuous, linear finite element method for biharmonic equations on smooth surfaces by leveraging a surface gradient recovery operator to approximate second-order surface derivatives on an approximate surface. A residual stabilization enriches the numerical gradient and a weak edge-consistency term ensures stability without requiring a discrete Poincaré inequality, enabling optimal a priori error estimates in both the energy and $L^2$ norms despite geometric approximation errors. The authors establish stability, weak and strong gradient recovery properties, and precise error bounds, supported by numerical experiments on a sphere, a torus, and a heart-shaped surface that corroborate the theory and reveal gradient superconvergence. The approach offers a computationally efficient pathway for solving fourth-order PDEs on curved surfaces using standard $C^0$ elements while maintaining rigorous convergence guarantees and practical robustness to mesh quality.
Abstract
This paper presents an innovative continuous linear finite element approach to effectively solve biharmonic problems on surfaces. The key idea behind this method lies in the strategic utilization of a surface gradient recovery operator to compute the second-order surface derivative of a piecewise continuous linear function defined on the approximate surface, as conventional notions of second-order derivatives are not directly applicable in this context. By incorporating appropriate stabilizations, we rigorously establish the stability of the proposed formulation. Despite the presence of geometric error, we provide optimal error estimates in both the energy norm and $L^2$ norm. Theoretical results are supported by numerical experiments.
