Stable semi-implicit SDC methods for conservation laws
Joerg Stiller
TL;DR
This work introduces a robust family of semi‑implicit spectral deferred correction (SDC) methods for conservation laws, built from a Lax–Wendroff–inspired splitting that treats convection explicitly while handling diffusion and sources implicitly. The approach uses right‑sided Radau points, yielding high‑order accuracy and strong stability properties (notably $L$-stability up to order 11) with linear systems that are positive semidefinite. The methods are shown to be equivalent to Radau IIA collocation and to DG in time, and are validated with 1D DG spatial discretizations on convection–diffusion, Burgers, Euler, and Navier–Stokes problems, including shock scenarios and high CFL runs. Numerical experiments indicate excellent stability and accuracy, outperforming some IMEX methods at higher accuracies and remaining competitive with (and sometimes superior to) explicit RK schemes when diffusion plays a significant role. The work also notes avenues for acceleration (e.g., multilevel methods) and extension to multidimensional problems.
Abstract
Semi-implicit spectral deferred correction (SDC) methods provide a systematic approach to construct time integration methods of arbitrarily high order for nonlinear evolution equations including conservation laws. They converge towards $A$- or even $L$-stable collocation methods, but are often not sufficiently robust themselves. In this paper, a family of SDC methods inspired by an implicit formulation of the Lax-Wendroff method is developed. Compared to fully implicit approaches, the methods have the advantage that they only require the solution of positive definite or semi-definite linear systems. Numerical evidence suggests that the proposed semi-implicit SDC methods with Radau points are $L$-stable up to order 11 and require very little diffusion for orders 13 and 15. The excellent stability and accuracy of these methods is confirmed by numerical experiments with 1D conservation problems, including the convection-diffusion, Burgers, Euler and Navier-Stokes equations.
