The Riemann Problem for the Transportation Equations in Gas Dynamics

The Riemann Problem for the Transportation Equations in Gas Dynamics
Author: Wancheng Sheng
Publisher: American Mathematical Soc.
Total Pages: 93
Release: 1999
Genre: Mathematics
ISBN: 0821809474

In this volume, the one-dimensional and two-dimensional Riemann problems for the transportation equations in gas dynamics are solved constructively. In either the 1-D or 2-D case, there are only two kinds of solutions: one involves Dirac delta waves, and the other involves vacuums, which has been merely discussed so far. The generalized Rankine-Hugoniot and entropy conditions for Dirac delta waves are clarified with viscous vanishing method. All of the existence, uniqueness and stability for viscous perturbations are proved analytically

The Two-Dimensional Riemann Problem in Gas Dynamics

The Two-Dimensional Riemann Problem in Gas Dynamics
Author: Jiequan Li
Publisher: Routledge
Total Pages: 318
Release: 2022-02-13
Genre: Mathematics
ISBN: 1351408887

The Riemann problem is the most fundamental problem in the entire field of non-linear hyperbolic conservation laws. Since first posed and solved in 1860, great progress has been achieved in the one-dimensional case. However, the two-dimensional case is substantially different. Although research interest in it has lasted more than a century, it has yielded almost no analytical demonstration. It remains a great challenge for mathematicians. This volume presents work on the two-dimensional Riemann problem carried out over the last 20 years by a Chinese group. The authors explore four models: scalar conservation laws, compressible Euler equations, zero-pressure gas dynamics, and pressure-gradient equations. They use the method of generalized characteristic analysis plus numerical experiments to demonstrate the elementary field interaction patterns of shocks, rarefaction waves, and slip lines. They also discover a most interesting feature for zero-pressure gas dynamics: a new kind of elementary wave appearing in the interaction of slip lines-a weighted Dirac delta shock of the density function. The Two-Dimensional Riemann Problem in Gas Dynamics establishes the rigorous mathematical theory of delta-shocks and Mach reflection-like patterns for zero-pressure gas dynamics, clarifies the boundaries of interaction of elementary waves, demonstrates the interesting spatial interaction of slip lines, and proposes a series of open problems. With applications ranging from engineering to astrophysics, and as the first book to examine the two-dimensional Riemann problem, this volume will prove fascinating to mathematicians and hold great interest for physicists and engineers.

Riemann Problems and Jupyter Solutions

Riemann Problems and Jupyter Solutions
Author: David I. Ketcheson
Publisher: SIAM
Total Pages: 178
Release: 2020-06-26
Genre: Mathematics
ISBN: 1611976219

This book addresses an important class of mathematical problems (the Riemann problem) for first-order hyperbolic partial differential equations (PDEs), which arise when modeling wave propagation in applications such as fluid dynamics, traffic flow, acoustics, and elasticity. The solution of the Riemann problem captures essential information about these models and is the key ingredient in modern numerical methods for their solution. This book covers the fundamental ideas related to classical Riemann solutions, including their special structure and the types of waves that arise, as well as the ideas behind fast approximate solvers for the Riemann problem. The emphasis is on the general ideas, but each chapter delves into a particular application. Riemann Problems and Jupyter Solutions is available in electronic form as a collection of Jupyter notebooks that contain executable computer code and interactive figures and animations, allowing readers to grasp how the concepts presented are affected by important parameters and to experiment by varying those parameters themselves. The only interactive book focused entirely on the Riemann problem, it develops each concept in the context of a specific physical application, helping readers apply physical intuition in learning mathematical concepts. Graduate students and researchers working in the analysis and/or numerical solution of hyperbolic PDEs will find this book of interest. This includes mathematicians, as well as scientists and engineers, working on wave propagation problems. Educators interested in developing instructional materials using Jupyter notebooks will also find this book useful. The book is appropriate for courses in Numerical Methods for Hyperbolic PDEs and Analysis of Hyperbolic PDEs, and it can be a great supplement for courses in computational fluid dynamics, acoustics, and gas dynamics.

Riemann Problem for the Transportation Equations in Gas Dynamics

Riemann Problem for the Transportation Equations in Gas Dynamics
Author: Wancheng Sheng
Publisher: Oxford University Press, USA
Total Pages: 93
Release: 2014-09-11
Genre: MATHEMATICS
ISBN: 9781470402433

In this volume, the one-dimensional and two-dimensional Riemann problems for the transportation equations in gas dynamics are solved constructively. In either the 1-D or 2-D case, there are only two kinds of solutions: one involves Dirac delta waves, and the other involves vacuums, which has been merely discussed so far. The generalized Rankine-Hugoniot and entropy conditions for Dirac delta waves are clarified with viscous vanishing method. All of the existence, uniqueness and stability for viscous perturbations are proved analytically

Rational Homotopical Models and Uniqueness

Rational Homotopical Models and Uniqueness
Author: Martin Majewski
Publisher: American Mathematical Soc.
Total Pages: 175
Release: 2000
Genre: Mathematics
ISBN: 0821819208

The main goal of this paper is to prove the following conjecture of Baues and Lemaire: the differential graded Lie Tlgebra associated with the Sullivan model of a space is homotopy equivalent to its Quillen model. In addition we show the same for the cellular Lie algebra model which we build from the simplicial analog of the classical Adams-Hilton model. It turns out that this cellular Lie algebra model is one link in a chain of models connecting the models of Quillen and Sullivan.The key result which makes all this possible is Anick's correspondence between differential graded Lie algebras and Hopf algebras up to homotopy. In addition we show that the Quillen model is a rational homotopical equivalence, and we conclude the same for the other models using our main result. Theconstruction of the three models is given in detail. The background from homotopy theory, differential algebra, and algebra is presented in great generality.

Inverses of Disjointness Preserving Operators

Inverses of Disjointness Preserving Operators
Author: Yuri A. Abramovich
Publisher: American Mathematical Soc.
Total Pages: 178
Release: 2000
Genre: Mathematics
ISBN: 0821813978

This book is intended for graduate students and research mathematicians interested in operator theory, functional analysis, and vector lattices

Cocycles of CCR Flows

Cocycles of CCR Flows
Author: B. V. Rajarama Bhat
Publisher: American Mathematical Soc.
Total Pages: 130
Release: 2001
Genre: Mathematics
ISBN: 0821826328

We study the partially ordered set of quantum dynamical semigroups dominated by a given semigroup on the algebra of all bounded operators on a Hilbert space. For semigroups of *-endomorphisms this set can be described through cocycles. This helps us to prove a factorization theorem for dilations and to show that minimal dilations of quantum dynamical semigroups with bounded generators can be got through Hudson-Parthasarathy cocycles.

Resolving Markov Chains onto Bernoulli Shifts via Positive Polynomials

Resolving Markov Chains onto Bernoulli Shifts via Positive Polynomials
Author: Brian Marcus
Publisher: American Mathematical Soc.
Total Pages: 114
Release: 2001
Genre: Biography & Autobiography
ISBN: 0821826468

The two parts of this monograph contain two separate but related papers. The longer paper in Part A obtains necessary and sufficient conditions for several types of codings of Markov chains onto Bernoulli shifts. It proceeds by replacing the defining stochastic matrix of each Markov chain by a matrix whose entries are polynomials with positive coefficients in several variables; a Bernoulli shift is represented by a single polynomial with positive coefficients, $p$. This transforms jointly topological and measure-theoretic coding problems into combinatorial ones. In solving the combinatorial problems in Part A, the work states and makes use of facts from Part B concerning $p DEGREESn$ and its coefficients. Part B contains the shorter paper on $p DEGREESn$ and its coefficients, and is independ