High Order Edge Sensors with ℓ1 Regularization for Enhanced Discontinuous Galerkin Methods

This paper investigates the use of ℓ1 regularization for solving hyperbolic conservation laws based on high order discontinuous Galerkin (DG) approximations. We first use the polynomial annihilation method to construct a high order edge sensor which enables us to flag troubled elements. The DG approximation is enhanced in these troubled regions by activating ℓ1 regularization to promote sparsity in the corresponding jump function of the numerical solution. The resulting ℓ1 optimization problem is efficiently implemented using the alternating direction method of multipliers. By enacting ℓ1 regularization only in troubled cells, our method remains accurate and efficient, as no additional regularization or expensive iterative procedures are needed in smooth regions. We present results for the inviscid Burgers' equation as well as a nonlinear system of conservation laws using a nodal collocation-type DG method as a solver.