我们考虑以下带源项的一维标量守恒律的平衡格式:d_t u + d_x f(u) + z'(x) b(u) = 0。更准确地说,我们对该方程的初边值问题的数值逼近感兴趣。虽然我们的主要关注点是收敛性结果,但我们还必须将Otto的熵解概念推广到带源项的守恒律。为了得到唯一性,我们证明了一个推广,即所谓的熵过程解,是唯一的并且与熵解一致。如果初始和边界数据本质有界,我们可以建立收敛到熵解。通过证明数值解有界,我们可以提取一个弱*收敛子序列。将其极限识别为熵过程解需要一些努力,因为我们不能在这里使用Kruzkov型熵对。我们限制自己使用Engquist-Osher通量,并识别任意熵对的数值熵通量。通过唯一性结果,该格式逼近熵解,而Vovelle的一个结果则保证对于有限的p,收敛在L^p中是强的。
英文摘要:
We consider well-balanced schemes for the following 1D scalar conservation law with source term: d_t u + d_x f(u) + z'(x) b(u) = 0. More precisely, we are interested in the numerical approximation of the initial boundary value problem for this equation. While our main concern is a convergence result, we also have to extend Otto's notion of entropy solutions to conservation laws with a source term. To obtain uniqueness, we show that a generalization, the so-called entropy process solution, is unique and coincides with the entropy solution. If the initial and boundary data are essentially bounded, we can establish convergence to the entropy solution. Showing that the numerical solutions are bounded we can extract a weak*-convergent subsequence. Identifying its limit as an entropy process solution requires some effort as we cannot use Kruzkov-type entropy pairs here. We restrict ourselves to the Engquist-Osher flux and identify the numerical entropy flux for an arbitrary entropy pair. By the uniqueness result, the scheme then approximates the entropy solution and a result by Vovelle then guarantees that the convergence is strong in L^p for finite p.
A high-order velocity-based discontinuous Galerkin scheme for the shallow water equations: local conservation, entropy stability, well-balanced property, and positivity preservation
Well-balanced adaptive compact approximate Taylor methods for systems of balance laws
用于守恒律系统的紧致近似泰勒(CAT)方法由Carrillo和Pares在2019年引入。这些方法基于一种策略,允许一个扩展的高阶Lax-Wendroff方法的非线性系统,而不使用Cauchy-Kovalevskaya程序,具有任意偶数阶的精度2 p和使用(2 p + 1)-点拉伸,其中p是一个任意的正整数。最近在2021年,Carrillo,Macca,Pares,Russo和Zorio引入了一种策略来消除CAT方法产生的不连续性附近的虚假振荡。这种策略导致了所谓的自适应CAT(ACAT)方法,其中精度的顺序,从而宽度的stentrum,适应于局部光滑的解决方案。本文的目标是将CAT和ACAT方法推广到平衡律系统。为此,源项被写为其不定积分的导数,该不定积分被形式上视为通量函数。的方法以及平衡的属性进行了讨论,并提出了一个变种,允许在原则上保持任何固定的解决方案。所得到的方法,然后应用到一些系统,从一个线性标量守恒律的二维欧拉方程与重力,通过Burgers方程与源项和一维浅水方程:在几个数值试验的顺序和良好的平衡性能进行检查。
Well-balanced high order schemes on non-uniform grids and entropy residuals
Dipartimento di Scienza e Alta Tecnologia Università dell’Insubria(因苏布里亚大学科学与技术系);Dipartimento di Matematica “G. Peano” Università di Torino(都灵大学G.佩阿诺数学系)
A central-upwind scheme for open water flow in a wet/dry multiply-connected channel network
Institute of Mathematical Machines & System Problems, Ukrainian National Academy of Sciences(乌克兰国家科学院数学机器与系统问题研究所);Institute of Environmental Radioactivity, Fukushima University(福岛大学环境放射性研究所)
Entropy analysis and entropy stable DG methods for the 1D shallow water moment equations
Bernoulli Institute, University of Groningen(格罗宁根大学伯努利研究所);Department of Mathematics, Linköping University(林雪平大学数学系);Department of Mathematics, Computer Science and Statistics, Ghent University(根特大学数学、计算机科学和统计系)
Energy relaxation approximation for the compressible multicomponent flows in thermal nonequilibrium
本文用有限体积法对多维无粘、非平衡、高温流动进行了数值逼近。它致力于分析的数值格式的逼近双曲型方程组的齐次形式。我们从多变气体的单组分可压缩欧拉方程的数值方案中推导出一个设计该模型数值方案的一般框架。在多方气体绝热指数的一个非常简单的条件下,多组分体系的方案具有与单组分体系相同的性质:离散熵不等式,分密度和内能的正性,质量分数的离散最大值原理,熵的离散最小值原理.我们的方法将能量松弛[Coquel和Perthame,\textit{SIAM J. Numer. Anal.},35(1998),2223- 2249]扩展到多组分欧拉系统。在瞬时松弛极限下,我们证明了该解形式上收敛于多分量欧拉方程的唯一稳定的平衡解。然后,我们使用这个框架从多方欧拉系统的三个方案中设计数值方案:Goddern精确黎曼解算子[Goddern,Math. Sbornik,47(1959),271- 306]和HLL [Harten等人,SIAM Rev.,25(1983),35- 61]和基于压力松弛的[Bouchut,Nonlinear stability of finite volume methods for hyperbolic conservation laws and well balanced schemes for sources,Frontiers in Mathematics,Birkh…