检索结果-南通市图书馆

TIME-PERIODIC ISENTROPIC SUPERSONIC euler FLOWS IN ONE-DIMENSIONAL DUCTS DRIVING BY PERIODIC BOUNDARY CONDITIONS

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2019年第2期39卷 403-412页

作者： Hairong YUAN School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical Practice East China Normal University

We show existence of time-periodic supersonic solutions in a finite interval, after certain start-up time depending on the length of the interval, to the one space-dimensional isentropic compressible euler equations, subjected to periodic boundary conditions. Both classical solutions and weak entropy solutions, as well as high-frequency limiting behavior are considered. The proofs depend on the theory of Cauchy problems of genuinely nonlinear hyperbolic systems of conservation laws.

关键词： supersonic flow isentropic compressible euler equations duct time-periodic solution initial-boundary-value problem

Solving the Nonlinear Variable Order Fractional Differential Equations by Using euler Wavelets

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2019年第2期118卷 339-350页

作者： Yanxin Wang Li Zhu Zhi Wang School of Science Ningbo University of TechnologyNingboChina.

An euler wavelets method is proposed to solve a class of nonlinear variable order fractional differential equations in this *** properties of euler wavelets and their operational matrix together with a family of piecewise functions are first *** they are utilized to reduce the problem to the solution of a nonlinear system of algebraic *** the convergence of the euler wavelets basis is *** method is computationally attractive and some numerical examples are provided to illustrate its high accuracy.

关键词： euler wavelets variable order fractional differential equations caputo fractional derivatives operational matrix convergence analysis.

Convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible euler equations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第2期49卷 255-266页

作者： XIAO Ling, LI Fucai & WANG Shu Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100080, China Department of Mathematics, Nanjing University, Nanjing 210093, China College of Applied Sciences, Beijing University of Technology, Beijing 100022, China 1. Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China 2. Department of Mathematics Nanjing University Nanjing 210093 China 3. College of Applied Sciences Beijing University of Technology Beijing 100022 China

We establish the convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible euler equations in this paper. The convergence is rigorously proved on the time interval where the smooth solution to the incompressible euler equations exists. The proof relies on the compactness argument and the so-called relative-entropy method.

关键词： Vlasov-Poisson-Fokker-Planck system incompressible euler equations relative-entropy method.

Deduction and application of generalized euler formula in topological relation of geographic information system (GIS)

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第8期47卷 749-759页

作者： ZHANG Shuqing1, ZHANG Junyan1,2 & ZHANG Bai1 Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Changchun 130012, China Northeast Design Institute of China City Planning and Engineering, Changchun 130012, China 1. Northeast Institute of Geography and Agricultural Ecology Chinese Academy of Sciences 130012 Changchun China 2. Northeast Design Institute of China City Planning and Engineering 130012 Changchun China

By combining geographic information system (GIS), a new conception of “group” in which covers the complex connected region is introduced in the paper. Based on the conception of group, a generalized euler formula and its properties are deduced and proved. The paper also describes the mathematical principles of generating topological information of polygon in GIS maps and the methods for checking up the veracity of topological relations of the map with euler formula and general euler formula. We have also obtained the quantitative relations among real nodes, chains, islands and groups with the formulas. At the same time, the paper introduces Whole Sphere Stereographic (WSS) projection into the GIS, and defines a new conception of “sea”. The deduction of general euler formula and the introduction of WSS projection to GIS have developed new ways of delineating GIS topological models from plane to sphere and even constructing three dimensional (3-D) topological models.

关键词： euler formula,general euler formula,geographic information system,topological relation.

Convergence to diffusion waves for solutions of euler equations with time-depending damping on quadrant

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2019年第1期62卷 33-62页

作者： Haibo Cui Haiyan Yin Changjiang Zhu Limei Zhu School of Mathematical Sciences Huaqiao University School of Mathematics South China University of Technology

This paper is concerned with the asymptotic behavior of the solution to the euler equations with time-depending damping on quadrant(x,t)∈R^+×R^+,with the null-Dirichlet boundary condition or the null-Neumann boundary condition on u. We show that the corresponding initial-boundary value problem admits a unique global smooth solution which tends timeasymptotically to the nonlinear diffusion wave. Compared with the previous work about euler equations with constant coefficient damping, studied by Nishihara and Yang(1999), and Jiang and Zhu(2009, Discrete Contin Dyn Syst), we obtain a general result when the initial perturbation belongs to the same space. In addition,our main novelty lies in the fact that the cut-off points of the convergence rates are different from our previous result about the Cauchy problem. Our proof is based on the classical energy method and the analyses of the nonlinear diffusion wave.

关键词： euler equations with time-depending damping nonlinear diffusion waves initial-boundary value problem decay estimates

Propagation of oscillations to 2D incompressible euler equations

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 1998年第5期41卷 449-460页

作者：张平吴广荣仇庆久 1. Institute of Mathematics Chinese Academy of Sciences 100080 Beijing China 2. Department of Mathematics Nanjing University 210093 Nanjing China

The asymptotic expansions are studied for the vorticity $\{ \omega ^ \in (t,x)\} $ to 2D incompressible euler equations with-initial vorticity $\omega _0^ \in (x) = \omega _0 (x) + \varepsilon \omega _0^1 \left( {x,\frac{{\varphi _0 (x)}}{\varepsilon }} \right)$ , where ?0(x) satisfies |d ?0(x)|≠0 on the support of $\omega _0^1 \left( { \cdot ,\theta } \right),\theta \in {\rm T}$ and $\omega _0 \left( x \right)(resp. \omega _0^1 (x,\theta ))$ is sufficiently smooth and with compact support in ?2 (resp. ?2×T) The limit,v(t,x), of the corresponding velocity fields {v ?(t,x)} is obtained, which is the unique solution of (E) with initial vorticity ω0(x). Moreover, $\omega ^ \in (t,x) = \omega (t,x) + \varepsilon \omega ^1 \left( {t,x,\frac{{\varphi (t,x)}}{\varepsilon }} \right) + o(\varepsilon ){\text{ }}in{\text{ }}C([0,\infty ),{\text{ L}}^p $ (?2)) for all 1?p∞, where $\omega (t,x) = \partial _1 \upsilon _2 (t,x) - \partial _2 \upsilon _1 \left( {t,x} \right),\omega ^1 (t,x,\theta )$ and ?(t,x) satisfy some modulation equation and eikonal equation, respectively.

关键词： Incompressible euler equations paradifferential calculus propagation of oscillations Young measures.

Global existence of smooth solutions to two-dimensional compressible isentropic euler equations for Chaplygin gases

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2010年第3期53卷 719-738页

作者： KONG DeXing 1 , LIU KeFeng 2 & WANG YuZhu 3, 1 Department of Mathematics, Zhejiang University, Hangzhou 310027, China 2 Department of Mathematics, University of California at Los Angeles, CA 90095, USA 3 Department of Mathematics, Shanghai Jiao Tong University, Shanghai 200248, China 1. Department of Mathematics Zhejiang University Hangzhou 310027 China2. Department of Mathematics University of California at Los Angeles Los Angeles CA 90095 USA3. Department of Mathematics Shanghai Jiao Tong University Shanghai 200248 China

In this paper we investigate the two-dimensional compressible isentropic euler equations for Chaplygin gases. Under the assumption that the initial data is close to a constant state and the vorticity of the initial velocity vanishes, we prove the global existence of the smooth solution to the Cauchy problem for twodimensional flow of Chaplygin gases.

关键词： Chaplygin gases compressible euler equations irrotational flow null condition Cauchy problem smooth solution

Two-Dimensional euler Adaptive Mesh Method on Detonation

在线全文

学校读者我要写书评

暂无评论

Journal of Beijing Institute of Technology 2009年第2期18卷 141-145页

作者：郝鹏程冯其京姚雯 Beijing Institute of Applied Physics and Computational Mathematics

The adaptive mesh refinement （AMR） method is applied in the 2-D euler multi-component elasticplastic hydrodynamics code （MEPH2Y）. It is applied on detonation. Firstly, the AMR method is described, including a conservative spatial interpolation, the time integration methodology with the adapitve time increment and an adaptive computational region method. The advantage of AMR technique is exhibited by numerical examples, including the 1-D C-J detonation and the 2-D implosion ignited from a single point. Results show that AMR can promote the computational efficiency, keeping the accuracy in interesting regions.

关键词： adaptive mesh refinement (AMR) detonation two-dimension euler numerical simulation

On relationship between convergence ball of euler iteration in Banach spaces and its dynamical behavior on Riemann spheres

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2003年第3期46卷 376-382页

作者：王何宇李冲王兴华 Computing Center Zhejiang University Department of Mathematics Zhejiang UniversityHangzhou 310028China Department of Mathematics Zhejiang University

The relationship between the convergence ball of the euler iteration in Banach Spaces and itsexclusive fixed points on Riemann spheres is investigated. By using an exclusive fixed point of the euleriteration, the convergence ball is determined accurately for a class of operators whose derivatives satisfy somegeneralized Lipschitz condition on Banach spaces.

关键词： solution ofoperator equation, the euler iteration, convergence ball, exclusive fixedpoint, complex analytic dynamical system.