DISCONTINUOUS GALERKIN FINITE ELEMENT APPROXIMATION OF NONDIVERGENCE FORM ELLIPTIC EQUATIONS WITH CORDèS COEFFICIENTS?

摘要

Nondivergence form elliptic equations with discontinuous coefficients do not generally possess a weak formulation, thus presenting an obstacle to their numerical solution by classical finite element methods. We propose a new hp-version discontinuous Galerkin finite element method for a class of these problems which satisfy the Cordès condition. It is shown that the method exhibits a convergence rate that is optimal with respect to the mesh size h and suboptimal with respect to the polynomial degree p by only half an order. Numerical experiments demonstrate the accuracy of the method and illustrate the potential of exponential convergence under hp-refinement for problems with discontinuous coefficients and nonsmooth solutions.