@Article{IJNAM-17-6, author = {Mahboub, Baccouch}, title = {Asymptotically Exact a Posteriori Error Estimates for the Local Discontinuous Galerkin Method for Nonlinear KdV Equations in One Space Dimension}, journal = {International Journal of Numerical Analysis and Modeling}, year = {2020}, volume = {17}, number = {6}, pages = {767--793}, abstract = {
In this paper, we develop and analyze an implicit $a$ $posteriori$ error estimates for the local discontinuous Galerkin (LDG) method for nonlinear third-order Korteweg-de Vries (KdV) equations in one space dimension. First, we show that the LDG error on each element can be split into two parts. The first part is proportional to the $(p+1)$-degree right Radau polynomial and the second part converges with order $p$ $+$ $\frac{3}{2}$ in the $L^2$-norm, when piecewise polynomials of degree at most $p$ are used. These results allow us to construct $a$ $posteriori$ LDG error estimates. The proposed error estimates are computationally simple and are obtained by solving a local steady problem with no boundary conditions on each element. Furthermore, we prove that, for smooth solutions, these $a$ $posteriori$ error estimates converge at a fixed time to the exact spatial errors in the $L^2$-norm under mesh refinement. The order of convergence is proved to be $p$ $+$ $\frac{3}{2}$. Finally, we prove that the global effectivity index converges to unity at $\mathcal{O}(h^{\frac{1}{2}})$ rate. Several numerical examples are provided to illustrate the global superconvergence results and the convergence of the proposed error estimator.
}, issn = {2617-8710}, doi = {https://doi.org/2020-IJNAM-18350}, url = {https://global-sci.com/article/83042/asymptotically-exact-a-posteriori-error-estimates-for-the-local-discontinuous-galerkin-method-for-nonlinear-kdv-equations-in-one-space-dimension} }