@Article{NMTMA-9-579, author = {Tie Zhang and Lixin Tang}, title = {The Gradient Superconvergence of Bilinear Finite Volume Element for Elliptic Problems}, journal = {Numerical Mathematics: Theory, Methods and Applications}, year = {2016}, volume = {9}, number = {4}, pages = {579--594}, abstract = {
We study the gradient superconvergence of bilinear finite volume
element (FVE) solving the elliptic problems. First, a superclose
weak estimate is established for the bilinear form of the FVE
method. Then, we prove that the gradient approximation of the FVE
solution has the superconvergence property:
where denotes the average gradient on elements
containing point $P$ and $S$ is the set of optimal stress points
composed of the mesh points, the midpoints of edges and the centers of elements.