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Related papers: Bounds for Wave Speeds in the Riemann Problem: Dir…

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We utilize a three-dimensional manifold to solve Riemann Problems that arise from a system of two conservation laws with quadratic flux functions. Points in this manifold represent potential shock waves, hence its name wave manifold. This…

Upcoming large-scale-structure surveys can shed new light on the properties of dark energy. In particular, if dark energy is a dynamical component, it must have spatial perturbations. Their behaviour is regulated by the speed of sound…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-10 Linda Blot , Pier Stefano Corasaniti , Fabian Schmidt

A new Hamiltonian formulation for the fully nonlinear water-wave problem over variable bathymetry is derived, using an exact, vertical series expansion of the velocity potential, in conjunction with Luke's variational principle. The…

Fluid Dynamics · Physics 2017-04-14 Christos Papoutsellis , Gerassimos Athanassoulis

This paper introduces a novel wave front tracking framework for reconstructing unknown flux functions in $2\times 2$ hyperbolic conservation laws, extending beyond the well-studied scalar case. By analyzing Riemann solutions at fixed…

Analysis of PDEs · Mathematics 2025-11-25 Chaohua Duan , Yan Jiang , Hongyu Liu , Wenjian Peng

We study the wave equation on a bounded domain of $\mathbb R^m$ and on a compact Riemannian manifold $M$ with boundary. We assume that the coefficients of the wave equation are unknown but that we are given the hyperbolic…

Analysis of PDEs · Mathematics 2020-09-23 Anna Kirpichnikova , Jussi Korpela , Matti Lassas , Lauri Oksanen

We study the resolution of discontinuous singularities in gas dynamics via rarefaction waves. The mechanism is well-understood in the one dimensional case. We will prove the non-nonlinear stability of the Riemann problem for…

Analysis of PDEs · Mathematics 2024-09-20 Tian-Wen Luo , Pin Yu

A number of physical phenomena are described by nonlinear hyperbolic equations. Presence of discontinuous solutions motivates the necessity of development of reliable numerical methods based on the fundamental mathematical properties of…

Computational Physics · Physics 2007-05-23 A. G. Kulikovskii , N. V. Pogorelov , A. Yu Semenov

Solution of Helmholtz equation with impedance boundary condition on finite interval is equivalently reformulated as steady state of initial boundary value problem for first order hyperbolic system of partial differential equations.…

Numerical Analysis · Mathematics 2018-06-19 Ramaz Botchorishvili , Tamar Janelidze

We formulated a problem on hypersonic limit of two-dimensional steady non-isentropic compressible Euler flows passing a straight wedge. It turns out that Mach number of the upcoming uniform supersonic flow increases to infinite may be taken…

Analysis of PDEs · Mathematics 2019-04-09 Aifang Qu , Hairong Yuan , Qin Zhao

We introduce a generalization of Glimm's random choice method, which provides us with an approximation of entropy solutions to quasilinear hyperbolic system of balance laws. The flux-function and the source term of the equations may depend…

Analysis of PDEs · Mathematics 2007-05-23 John M. Hong , Philippe G. LeFloch

For the 3-D quadratic quasilinear wave equations in exterior domains with Dirichlet or Neumann boundary conditions, the global existence or the maximal existence time of small data smooth solutions have been established in the past.…

Analysis of PDEs · Mathematics 2026-02-17 Fei Hou , Huicheng Yin , Meng Yuan

We study the boundary exact controllability for the quasilinear wave equation in the higher-dimensional case. Our main tool is the geometric analysis. We derive the existence of long time solutions near an equilibrium, prove the locally…

Analysis of PDEs · Mathematics 2007-05-23 Peng-Fei Yao

We have generalised the exact solution of the Riemann problem in special relativistic hydrodynamics for arbitrary tangential flow velocities. The solution is obtained by solving the jump conditions across shocks plus an ordinary…

Astrophysics · Physics 2017-05-17 Jose A. Pons , Jose Ma. Marti , Ewald Mueller

Kinetic or Boltzmann schemes are interesting alternatives to the macroscopic numerical methods for solving the hyperbolic conservation laws of gas dynamics. They utilize the particle-based description instead of the wave propagation models.…

Computational Physics · Physics 2016-12-26 N. Venkata Raghavendra , S. V. Raghurama Rao

This paper is concerned with the Riemann problem of one-dimensional Euler equations with a singular source. The exact solution of this Riemann problem contains a stationary discontinuity induced by the singular source, which is different…

Analysis of PDEs · Mathematics 2022-03-10 Changsheng Yu , Tiegang Liu , Chengliang Feng

We derive various approximations for the solutions of nonlinear hyperbolic systems with fastly oscillating initial data. We first provide error estimates for the so-called slowly varying envelope, full dispersion, and Schr\"odinger…

Analysis of PDEs · Mathematics 2007-12-27 Mathieu Colin , David Lannes

In Newtonian and relativistic hydrodynamics the Riemann problem consists of calculating the evolution of a fluid which is initially characterized by two states having different values of uniform rest-mass density, pressure and velocity.…

General Relativity and Quantum Cosmology · Physics 2009-11-07 L. Rezzolla , O. Zanotti

An exact macroscopic extended model for ultrarelativistic gases, with an arbitrary number of moments, is present in the literature. Here we exploit equations determining wave speeds for that model. We find interesting results; for example,…

Mathematical Physics · Physics 2010-12-08 F. Borghero , F. Demontis , S. Pennisi

We derive explicit pointwise bounds for the spatial derivative $\left| \frac{\partial V}{\partial x} \right|$ of solutions to linear parabolic PDEs with Neumann boundary conditions. The bound is fully explicit in the sense that it depends…

Probability · Mathematics 2025-12-25 C Ciccarella

We establish the hydrodynamic limit of the one-dimensional Boltzmann equation with hard-sphere collisions toward Riemann solutions of the compressible Euler system. The Riemann solutions covered by our result include generic superpositions…

Analysis of PDEs · Mathematics 2026-05-26 Mingi Choe , Moon-jin Kang , Chanwoo Kim