arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.03521math.NAcs.NA
收藏

非线性双曲型方程间断Galerkin离散的熵稳定性和保性质限制器

Entropy stabilization and property-preserving limiters for discontinuous Galerkin discretizations of nonlinear hyperbolic equations

Dmitri Kuzmin

摘要:

本文提出的方法之间的差距桥梁熵稳定和保正间断Galerkin(DG)方法的非线性双曲型问题。熵稳定性属性,并可选地,保存的单元平均值的局部边界分别使用基于熵条件和离散最大值原理的通量限制器。熵生产的(有限的)梯度的分段线性DG近似的约束使用Rusanov型熵粘度,提出了由Abgrall的上下文中的节点有限元近似。我们铸造他的代数熵修复成一种适合于任意多项式基地,特别是模态DG方法的形式。熵稳定项的泰勒基表示揭示了它以类似于斜率限制的方式惩罚解梯度,并且需要半隐式处理以实现期望的效果。Rusanov熵修正的隐式Taylor基版本保留了元素质量矩阵的稀疏模式。因此,没有线性系需要解决,如果泰勒基是正交的,并采取显式处理的其余条款。基于顶点的斜率限制器的可选应用约束分段线性DG解以单元平均值的局部最大值和最小值为界。熵稳定与通量和斜率限制的组合导致具有所有期望性质的约束近似。数值研究的新的限制技术和熵校正程序进行两个标量二维测试问题的非线性和非凸通量函数。

英文摘要:

The methodology proposed in this paper bridges the gap between entropy stable and positivity-preserving discontinuous Galerkin (DG) methods for nonlinear hyperbolic problems. The entropy stability property and, optionally, preservation of local bounds for the cell averages are enforced using flux limiters based on entropy conditions and discrete maximum principles, respectively. Entropy production by the (limited) gradients of the piecewise-linear DG approximation is constrained using Rusanov-type entropy viscosity, as proposed by Abgrall in the context of nodal finite element approximations. We cast his algebraic entropy fix into a form suitable for arbitrary polynomial bases and, in particular, for modal DG approaches. The Taylor basis representation of the entropy stabilization term reveals that it penalizes the solution gradients in a manner similar to slope limiting and requires semi-implicit treatment to achieve the desired effect. The implicit Taylor basis version of the Rusanov entropy fix preserves the sparsity pattern of the element mass matrix. Hence, no linear systems need to be solved if the Taylor basis is orthogonal and an explicit treatment of the remaining terms is adopted. The optional application of a vertex-based slope limiter constrains the piecewise-linear DG solution to be bounded by local maxima and minima of the cell averages. The combination of entropy stabilization with flux and slope limiting leads to constrained approximations that possess all desired properties. Numerical studies of the new limiting techniques and entropy correction procedures are performed for two scalar two-dimensional test problems with nonlinear and nonconvex flux functions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑