7,231 research outputs found
A posteriori analysis of fully discrete method of lines DG schemes for systems of conservation laws
We present reliable a posteriori estimators for some fully discrete schemes
applied to nonlinear systems of hyperbolic conservation laws in one space
dimension with strictly convex entropy. The schemes are based on a method of
lines approach combining discontinuous Galerkin spatial discretization with
single- or multi-step methods in time. The construction of the estimators
requires a reconstruction in time for which we present a very general framework
first for odes and then apply the approach to conservation laws. The
reconstruction does not depend on the actual method used for evolving the
solution in time. Most importantly it covers in addition to implicit methods
also the wide range of explicit methods typically used to solve conservation
laws. For the spatial discretization, we allow for standard choices of
numerical fluxes. We use reconstructions of the discrete solution together with
the relative entropy stability framework, which leads to error control in the
case of smooth solutions. We study under which conditions on the numerical flux
the estimate is of optimal order pre-shock. While the estimator we derive is
computable and valid post-shock for fixed meshsize, it will blow up as the
meshsize tends to zero. This is due to a breakdown of the relative entropy
framework when discontinuities develop. We conclude with some numerical
benchmarking to test the robustness of the derived estimator
On the convergence of a shock capturing discontinuous Galerkin method for nonlinear hyperbolic systems of conservation laws
In this paper, we present a shock capturing discontinuous Galerkin (SC-DG)
method for nonlinear systems of conservation laws in several space dimensions
and analyze its stability and convergence. The scheme is realized as a
space-time formulation in terms of entropy variables using an entropy stable
numerical flux. While being similar to the method proposed in [14], our
approach is new in that we do not use streamline diffusion (SD) stabilization.
It is proved that an artificial-viscosity-based nonlinear shock capturing
mechanism is sufficient to ensure both entropy stability and entropy
consistency, and consequently we establish convergence to an entropy
measure-valued (emv) solution. The result is valid for general systems and
arbitrary order discontinuous Galerkin method.Comment: Comments: Affiliations added Comments: Numerical results added,
shortened proo
Optimal Regularizing Effect for Scalar Conservation Laws
We investigate the regularity of bounded weak solutions of scalar
conservation laws with uniformly convex flux in space dimension one, satisfying
an entropy condition with entropy production term that is a signed Radon
measure. The proof is based on the kinetic formulation of scalar conservation
laws and on an interaction estimate in physical space.Comment: 24 pages, assumption (11) in Theorem 3.1 modified together with the
example on p. 7, one remark added after the proof of Lemma 4.3, some typos
correcte
Multidimensional Conservation Laws: Overview, Problems, and Perspective
Some of recent important developments are overviewed, several longstanding
open problems are discussed, and a perspective is presented for the
mathematical theory of multidimensional conservation laws. Some basic features
and phenomena of multidimensional hyperbolic conservation laws are revealed,
and some samples of multidimensional systems/models and related important
problems are presented and analyzed with emphasis on the prototypes that have
been solved or may be expected to be solved rigorously at least for some cases.
In particular, multidimensional steady supersonic problems and transonic
problems, shock reflection-diffraction problems, and related effective
nonlinear approaches are analyzed. A theory of divergence-measure vector fields
and related analytical frameworks for the analysis of entropy solutions are
discussed.Comment: 43 pages, 3 figure
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