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1.
E.Stanley Lee 《Journal of Mathematical Analysis and Applications》1976,54(2):591-601
The complex distillation column problem is formulated as a multipoint boundary value problem in difference equations. It is shown that this nonlinear multipoint boundary value problem can be solved easily by the quasilinearization technique. With very rough initial approximations, only ten iterations are needed to obtain a four digit accuracy in concentrations. The advantage of this approach is that the complex column can be solved in essentially the same way as the simple column with approximately the same computation requirements. 相似文献
2.
Stefan Ebenfeld 《Mathematical Methods in the Applied Sciences》2002,25(3):241-262
This is the third part of an article that is devoted to the theory of non‐linear initial boundary value problems. We consider coupled systems where each system is of higher order and of hyperbolic or parabolic type. Our goal is to characterize systematically all admissible couplings between systems of higher order and different type. By an admissible coupling we mean a condition that guarantees the existence, uniqueness and regularity of solutions to the respective initial boundary value problem. In part 1, we develop the underlying theory of linear hyperbolic and parabolic initial boundary value problems. Testing the PDEs with suitable functions we obtain a priori estimates for the respective solutions. In particular, we make use of the regularity theory for linear elliptic boundary value problems that was previously developed by the author. In part 2, we prove the local in time existence, uniqueness and regularity of solutions to quasilinear initial boundary value problems using the so‐called energy method. In the above sense the regularity assumptions about the coefficients and right‐hand sides define the admissible couplings. In part 3 at hand, we extend the results of part 2 to the nonlinear initial boundary value problem (4.2). In particular, assumptions (B8) and (B9) about the respective parameters correspond to the previous regularity assumptions and hence define the admissible couplings now. Moreover, we exploit assumptions (B8) and (B9) for the case of two coupled systems. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
3.
Stefan Ebenfeld 《Mathematical Methods in the Applied Sciences》2002,25(3):213-240
This is the second part of an article that is devoted to the theory of non‐linear initial boundary value problems. We consider coupled systems where each system is of higher order and of hyperbolic or parabolic type. Our goal is to characterize systematically all admissible couplings between systems of higher order and different type. By an admissible coupling we mean a condition that guarantees the existence, uniqueness and regularity of solutions to the respective initial boundary value problem. In part 1, we develop the underlying theory of linear hyperbolic and parabolic initial boundary value problems. Testing the PDEs with suitable functions we obtain a priori estimates for the respective solutions. In particular, we make use of the regularity theory for linear elliptic boundary value problems that was previously developed by the author. In part 2 at hand, we prove the local in time existence, uniqueness and regularity of solutions to the quasilinear initial boundary value problem (3.4) using the so‐called energy method. In the above sense the regularity assumptions (A6) and (A7) about the coefficients and right‐hand sides define the admissible couplings. In part 3, we extend the results of part 2 to non‐linear initial boundary value problems. In particular, the assumptions about the respective parameters correspond to the previous regularity assumptions and hence define the admissible couplings now. Moreover, we exploit the assumptions about the respective parameters for the case of two coupled systems. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
4.
E.Stanley Lee 《Journal of Mathematical Analysis and Applications》1976,54(2):602-615
The concept of treating multicomponent distillation problems as nonlinear boundary value problems in difference equations is used to solve columns at minimum reflux. Various computational algorithms are formulated based on the choice of different unknown variables and different boundary conditions. To show the quadratic convergence some typical algorithms are illustrated by numerical examples. It is shown that using very rough initial approximations or starting values, four to five digit accuracy is obtained in five to seven iterations. 相似文献
5.
Stefan Ebenfeld 《Mathematical Methods in the Applied Sciences》2002,25(3):179-212
In this article (which is divided in three parts) we investigate the non‐linear initial boundary value problems (1.2) and (1.3). In both cases we consider coupled systems where each system is of higher order and of hyperbolic or parabolic type. Our goal is to characterize systematically all admissible couplings between systems of higher order and different type. By an admissible coupling we mean a condition that guarantees the existence, uniqueness and regularity of solutions to the respective initial boundary value problem. In part 1 at hand, we develop the underlying theory of linear hyperbolic and parabolic initial boundary value problems. Testing the PDEs with suitable functions we obtain a priori estimates for the respective solutions. In particular, we make use of the regularity theory for linear elliptic boundary value problems that was previously developed by the author. In part 2, we prove the local in time existence, uniqueness and regularity of solutions to the quasilinear initial boundary value problem (1.2) using the so‐called energy method. In the above sense, the regularity assumptions about the coefficients and right‐hand sides define the admissible couplings. In part 3, we extend the results of part 2 to the non‐linear initial boundary value problem (1.3). In particular, the assumptions about the respective parameters correspond to the previous regularity assumptions and hence define the admissible couplings now. Moreover, we exploit the assumptions about the respective parameters for the case of two coupled systems. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
6.
I. Yu. Chudinovich 《Mathematical Methods in the Applied Sciences》1993,16(3):203-215
This work deals with four variants of boundary equations appearing if the third main initial boundary value problem is solved with the help of elastic retarded potentials. The solvability of these equations is proved, and the smoothness of their solutions researched. 相似文献
7.
Summary We explore the relation between the classical continuum model of Euler buckling and an iterated mapping which is not only
a mathematical discretization of the former but also has an exact, discrete mechanical analogue. We show that the latter possesses
great numbers of “parasitic” solutions in addition to the natural discretizations of classical buckling modes. We investigate
this rich bifurcational structure using both mechanical analysis of the boundary value problem and dynamical studies of the
initial value problem, which is the familiar standard map. We use this example to explore the links between discrete initial
and boundary value problems and, more generally, to illustrate the complex relations among physical systems, continuum and
discrete models and the analytical and numerical methods for their study. 相似文献
8.
We prove local existence, uniqueness, Hölder regularity in space and time, and smooth dependence in Hölder spaces for a general class of quasilinear parabolic initial boundary value problems with nonsmooth data. As a result the gap between low smoothness of the data, which is typical for many applications, and high smoothness of the solutions, which is necessary for the applicability of differential calculus to abstract formulations of the initial boundary value problems, has been closed. The theory works for any space dimension, and the nonlinearities in the equations as well as in the boundary conditions are allowed to be nonlocal and to have any growth. The main tools are new maximal regularity results (Griepentrog in Adv Differ Equ 12:781–840, 1031–1078, 2007) in Sobolev–Morrey spaces for linear parabolic initial boundary value problems with nonsmooth data, linearization techniques and the Implicit Function Theorem. 相似文献
9.
讨论推广的海底取油管振动方程的初边值问题和初值问题解的整体不存在性,对初边值问题推广了Gmira和Guedda得到的结果,对初值问题的结果是新的. 相似文献
10.
The major target of this paper is to construct new nonlinear boundary–initial value problems for Boussinesq–Burgers Equations, and derive the solutions of these nonlinear boundary–initial value problems by the simplified homogeneous balance method. The nonlinear transformation and its inversion between the Boussinesq–Burgers Equations and the linear heat conduction equation are firstly derived; then a new nonlinear boundary–initial value problem for the Boussinesq–Burgers equations with variable damping on the half infinite straight line is put forward for the first time, and the solution of this nonlinear boundary–initial value problem is obtained, especially, the decay mode solution of nonlinear boundary–initial value problem for the cylindrical (spherical) Boussinesq–Burgers equations is obtained. 相似文献
11.
Global Smooth Solutions and the Asymptotic Behavior of the Motion of a Viscous,Heat-conductive,One-dimensional Real Gas
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Ronghua Pan 《偏微分方程(英文版)》1998,11(3):273-288
The system of balance laws of mass, momentum and energy for a viscous, heal-conductive, one-dimensional real gas is considered. The existence of globally defined smooth solution to an initial boundary value problem is established. Because of the boundary conditions' effect, vacuum will be developped as time tends to infinity. 相似文献
12.
Mo Jiaqi 《高校应用数学学报(英文版)》2007,22(2):201-206
A class of nonlinear initial boundary value problems for reaction diffusion equations with boundary perturbation is considered. Under suitable conditions and using the theory of differential inequalities the asymptotic solution of the initial boundary value problems is studied. 相似文献
13.
Construction of Solutions and L^1-error Estimates of Viscous Methods for Scalar Conservation Laws with Boundary 总被引:4,自引:0,他引:4
Hong Xia LIU Tao PAN 《数学学报(英文版)》2007,23(3):393-410
This paper is concerned with an initial boundary value problem for strictly convex conservation laws whose weak entropy solution is in the piecewise smooth solution class consisting of finitely many discontinuities. By the structure of the weak entropy solution of the corresponding initial value problem and the boundary entropy condition developed by Bardos-Leroux Nedelec, we give a construction method to the weak entropy solution of the initial boundary value problem. Compared with the initial value problem, the weak entropy solution of the initial boundary value problem includes the following new interaction type: an expansion wave collides with the boundary and the boundary reflects a new shock wave which is tangent to the boundary. According to the structure and some global estimates of the weak entropy solution, we derive the global L^1-error estimate for viscous methods to this initial boundary value problem by using the matching travelling wave solutions method. If the inviscid solution includes the interaction that an expansion wave collides with the boundary and the boundary reflects a new shock wave which is tangent to the boundary, or the inviscid solution includes some shock wave which is tangent to the boundary, then the error of the viscosity solution to the inviscid solution is bounded by O(ε^1/2) in L^1-norm; otherwise, as in the initial value problem, the L^1-error bound is O(ε| In ε|). 相似文献
14.
15.
《Journal of Computational and Applied Mathematics》1987,17(3):345-354
This paper deals with the application of a variational method to a boundary value problem of the wave equation. Starting with an initial boundary value problem (which is given) introduction of a boundary condition at the final time leads to a boundary value problem with one of the initial conditions redundant. This redundant initial condition is used by the trial function of the direct method (of the Ritz type) which is employed to stationarize the variational principle. 相似文献
16.
本文研究非线性Sobolev-Calpern方程的初边值问题整体解的不存性即解的爆破问题,用能量估计方法并借助于Jensen不等式证明了非线性Soboliv-Galpern方程各种初边值问题在某些假设下不存在整体解。 相似文献
17.
Francesca Bucci 《Journal of Evolution Equations》2007,7(3):387-414
We consider a class of structural acoustics models with thermoelastic flexible wall. More precisely, the PDE system consists
of a wave equation (within an acoustic chamber) which is coupled to a system of thermoelastic plate equations with rotational
inertia; the coupling is strong as it is accomplished via boundary terms. Moreover, the system is subject to boundary thermal
control. We show that—under three different sets of coupled (mechanical/thermal) boundary conditions—the overall coupled system
inherits some specific regularity properties of its thermoelastic component, as it satisfies the same singular estimates recently established for the thermoelastic system alone. These regularity estimates are of central importance for (i) well-posedness
of Differential and Algebraic Riccati equations arising in the associated optimal control problems, and (ii) existence of
solutions to the semilinear initial/boundary value problem under nonlinear boundary conditions. The proof given uses as a critical ingredient a sharp trace theorem pertaining to second-order hyperbolic
equations with Neumann boundary data. 相似文献
18.
Simultaneous identification of diffusion coefficient,spacewise dependent source and initial value for one‐dimensional heat equation
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Zhi‐Xue Zhao Mapundi K. Banda Bao‐Zhu Guo 《Mathematical Methods in the Applied Sciences》2017,40(10):3552-3565
This paper deals with an inverse problem of determining the diffusion coefficient, spacewise dependent source term, and the initial value simultaneously for a one‐dimensional heat equation based on the boundary control, boundary measurement, and temperature distribution at a given single instant in time. By a Dirichlet series representation for the boundary observation, the identification of the diffusion coefficient and initial value can be transformed into a spectral estimation problem of an exponential series with measurement error, which is solved by the matrix pencil method. For the identification of the source term, a finite difference approximation method in conjunction with the truncated singular value decomposition is adopted, where the regularization parameter is determined by the generalized cross‐validation criterion. Numerical simulations are performed to verify the result of the proposed algorithm. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
19.
AMS (MOS) Subject Classification 76N10, 35G30 The existence and uniqueness of solutions, in Sobolev spaces, of the initial boundary value problem, global in time for the set of equations describing the flow of a barotropic viscous gas is investigated. A proof is deduced only for the case of inflow into a bounded domain valid for small initial and boundary conditions. 相似文献
20.
A. M. Denisov S. I. Solov’eva 《Computational Mathematics and Mathematical Physics》2013,53(11):1607-1613
The initial boundary value problem for the diffusion equation is considered in the case of spherical symmetry and an unknown initial condition. Additional information used for determining the unknown initial condition is an external volume potential whose density is the Laplace operator applied to the solution of the initial boundary value problem. The uniqueness of the solution of the inverse problem is studied depending on the parameters entering into the boundary conditions. It is shown that the solution of the inverse problem is either unique or not unique up to a one-dimensional linear subspace. 相似文献