Local discontinuous Galerkin method for a third order singularly perturbed problem of convection-diffusion type

10/24/2022

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by   Li Yan, et al.

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The local discontinuous Galerkin (LDG) method is studied for a third-order singularly perturbed problem of the convection-diffusion type. Based on a regularity assumption for the exact solution, we prove almost O(N^-(k+1/2)) (up to a logarithmic factor) energy-norm convergence uniformly in the perturbation parameter. Here, k≥ 0 is the maximum degree of piecewise polynomials used in discrete space, and N is the number of mesh elements. The results are valid for the three types of layer-adapted meshes: Shishkin-type, Bakhvalov-Shishkin type, and Bakhvalov-type. Numerical experiments are conducted to test the theoretical results.