论文标题
标量保护法的高阶有限元方法的基于耗散的WENO稳定
Dissipation-based WENO stabilization of high-order finite element methods for scalar conservation laws
论文作者
论文摘要
我们介绍了在高阶方法中使用加权基本上非振荡(WENO)重建的新观点。这项工作的主要重点是连续盖尔金(CG)近似的非线性稳定。所提出的方法还为不连续的Galerkin(DG)方法提供了一种有趣的替代方法。与runge - 与WENO重建覆盖有限元解决方案的Kutta DG方案不同,我们的方法使用基于重建的平滑度传感器来融合高阶和低阶稳定项的数值粘度算子。所谓的WENO近似在冲击附近引入了低阶非线性扩散,同时在确切溶液足够光滑的区域中保留线性稳定基线离散化的高阶精度。基本的重建程序在由网状细胞及其邻居组成的模板上执行Hermite插值。数值耗散的量取决于重建的候选多项式的部分衍生物与基础有限元近似的相对差异。所有衍生物都由使用的平滑度传感器考虑。为了评估CG-WENO方案的准确性,我们得出错误估计并执行数值实验。特别是,我们证明非线性稳定的一致性错误是$ p+1/2 $的顺序,其中$ p $是多项式学位。该估计对于一般网格是最佳的。对于均匀的网格和光滑的精确溶液,实验观察到的收敛速率高达$ P+1 $。
We present a new perspective on the use of weighted essentially nonoscillatory (WENO) reconstructions in high-order methods for scalar hyperbolic conservation laws. The main focus of this work is on nonlinear stabilization of continuous Galerkin (CG) approximations. The proposed methodology also provides an interesting alternative to WENO-based limiters for discontinuous Galerkin (DG) methods. Unlike Runge--Kutta DG schemes that overwrite finite element solutions with WENO reconstructions, our approach uses a reconstruction-based smoothness sensor to blend the numerical viscosity operators of high- and low-order stabilization terms. The so-defined WENO approximation introduces low-order nonlinear diffusion in the vicinity of shocks, while preserving the high-order accuracy of a linearly stable baseline discretization in regions where the exact solution is sufficiently smooth. The underlying reconstruction procedure performs Hermite interpolation on stencils consisting of a mesh cell and its neighbors. The amount of numerical dissipation depends on the relative differences between partial derivatives of reconstructed candidate polynomials and those of the underlying finite element approximation. All derivatives are taken into account by the employed smoothness sensor. To assess the accuracy of our CG-WENO scheme, we derive error estimates and perform numerical experiments. In particular, we prove that the consistency error of the nonlinear stabilization is of the order $p+1/2$, where $p$ is the polynomial degree. This estimate is optimal for general meshes. For uniform meshes and smooth exact solutions, the experimentally observed rate of convergence is as high as $p+1$.