A Divergence-Free Scott-Vogelius Finite Element Method for the Surface Stokes Problem

Abstract: We construct and analyze an exactly divergence-free Scott-Vogelius finite element method for the surface Stokes problem. The proposed scheme simultaneously enforces the tangentiality and incompressibility constructs exactly and has the same number of unknowns as the two-dimensional Euclidean discretization. Our construction extends the surface finite element framework of [10,11] to Scott--Vogelius discretizations defined on curved Clough--Tocher triangulations. In contrast to previous isoparametric Scott--Vogelius methods based on macro-element constructions, the present approach defines the finite element spaces directly on the refined surface triangulation, leading to a substantially simpler and more practical implementation. We prove inf-sup stability of the method and derive optimal-order convergence in the isoparametric regime.