A SUPERCONVERGENT ENSEMBLE HDG METHOD FOR PARAMETERIZED CONVECTION DIFFUSION EQUATIONS.

In this paper, we first devise an ensemble hybridizable discontinuous Galerkin (HDG) method to efficiently simulate a group of parameterized convection diffusion PDEs. These PDEs have different coefficients, initial conditions, source terms, and boundary conditions. The ensemble HDG discrete system shares a common coefficient matrix with multiple right-hand-side vectors; it reduces both computational cost and storage. We have two contributions in this paper. First, we derive an optimal L² convergence rate for the ensemble solutions on a general polygonal domain, which is the first such result in the literature. Second, we obtain a superconvergent rate for the ensemble solutions after an element-by-element postprocessing under some assumptions on the domain and the coefficients of the PDEs. We present numerical experiments to confirm our theoretical results. [ABSTRACT FROM AUTHOR]