利用三角形线性元的积分恒等式,给出了二维非定常对流占优扩散方程的特征线有限元解和真解的一致最优估计,并利用插值后处理算子,得到了有限元解梯度的一致超收敛估计,即只与初值和右端项有关,而与ε无关.
In this paper, the authors use the integral identities of triangular linear elements to prove a uniform optimal-order error estimate for the characteristics finite element solution of two-dimensional time-dependent advection-diffusion equations. Also the authors introduce an interpolation postprocessing operator to get the superconvergence estimate of ε weighted energy norm. The estimates above depend only on certain Sobolev norms of the initial and right-hand side data, but not on the scaling parameter ε.