arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv math/0702024math.APcs.NAmath.NA
收藏

双曲守恒律弱解中的边界层

Boundary layers in weak solutions to hyperbolic conservation laws

K. T. Joseph, Philippe G. LeFloch

AI总结:

研究非线性双曲守恒律系统初边值问题中不同正则化方法(粘性消失法和有限差分格式)产生的边界层,通过熵不等式和Young测度分析边界迹,并基于Dubois和LeFloch的术语提出适用于特征和非特征边界的边界条件公式。

摘要:

本文关注非线性双曲守恒律系统的初边值问题。我们研究了在熵不连续解的近似中可能出现的边界层。我们考虑了粘性消失法和有限差分格式(Lax-Friedrichs型格式、Godunov格式)。我们证明不同的正则化方法会产生不同的边界层。因此,只有在首先选择近似方案后才能制定边界条件。仅假设近似解的一致L∞界并处理L∞解,我们在每种情况下推导了边界层满足的几个熵不等式。引入Young测度来描述边界迹。当总变差有界时,边界Young测度退化为Dirac质量。通过上述分析,我们推导出适用于特征或非特征边界的边界条件的几种公式。每种公式基于一组可容许的边界值,遵循Dubois和LeFloch在“非线性双曲守恒律系统的边界条件”(J. Diff. Equa. 71 (1988), 93–122)中的术语。研究了这些集合的局部结构以及相应初边值问题的适定性。结果通过凸和非凸守恒律以及连续力学中的例子加以说明。

英文摘要:

This paper is concerned with the initial-boundary value problem for a nonlinear hyperbolic system of conservation laws. We study the boundary layers that may arise in approximations of entropy discontinuous solutions. We consider both the vanishing viscosity method and finite difference schemes (Lax-Friedrichs type schemes, Godunov scheme). We demonstrate that different regularization methods generate different boundary layers. Hence, the boundary condition can be formulated only if an approximation scheme is selected first. Assuming solely uniform L\infty bounds on the approximate solutions and so dealing with L\infty solutions, we derive several entropy inequalities satisfied by the boundary layer in each case under consideration. A Young measure is introduced to describe the boundary trace. When a uniform bound on the total variation is available, the boundary Young measure reduces to a Dirac mass. Form the above analysis, we deduce several formulations for the boundary condition which apply whether the boundary is characteristic or not. Each formulation is based a set of admissible boundary values, following Dubois and LeFloch's terminology in ``Boundary conditions for nonlinear hyperbolic systems of conservation laws'', J. Diff. Equa. 71 (1988), 93--122. The local structure of those sets and the well-posedness of the corresponding initial-boundary value problem are investigated. The results are illustrated with convex and nonconvex conservation laws and examples from continuum mechanics.

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。

↑