摘要:

We find new types of travelling wave solutions which join rest points of general 2- velocity models of the extended Boltzmann equation. The new solutions exhibit oscillations of the density around a stationary state. For the first time we derive the hydrodynamic approximations for such models. We study the travelling wave solutions of these equations as well, and compare them with the corresponding solutions of the kinetic equations.

ISSN:0041-1450    

DOI:10.1080/00411450008214527

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In this paper we study the real point spectrum of the multigroup neutron transport operator for a large class of unsymmetric collision matrices in bounded spatial domains. Necessary and sufficient conditions for existence, finiteness and sufficient conditions for infiniteness of the real point spectrum are given. Estimates of the number of real eigenvalues and localization results are also provided. The last part of this work is devoted to the properties of point spectrum which are specific to slab geometry with finite thickness.

ISSN:0041-1450    

DOI:10.1080/00411450008214528

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This paper describes a number of novel discontinuous finite element approximations to the linear Boltzmann transport equation. Two distinct approaches are used: one based on a dual set of basis functions and the other based on an upwinded characteristic method. In both approaches the boundary conditions are incorporated in a natural manner. The objective of the work is to develop a method that can follow abruptly-changing or nearly-discontinuous field variables, maintain solution feasibility e.g. non-negative physical quantities and achieve sparse direct coupling of the nodal moments when spherical harmonic angular descriptions arc used. The representative examples indicate that the methods offer attractive discretization methods for first-order partial differential equations. Appropriate solution methods for the resulting discretizations are also discussed.

ISSN:0041-1450    

DOI:10.1080/00411450008214529

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In this paper, the spectral properties of the streaming operator and transport operator with an external field are discussed in the Banach spaceL1(R3×R3). Some classical results of Voigt are extended to the linear Boltzmanh operator with an external field.

ISSN:0041-1450    

DOI:10.1080/00411450008214530

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Gelfand-Levitan method of differential equation restoration by its spectral function was developed for one velocity linear transport theory. Here this method is applied to a mulligroup transport theory. The systems of algebraic equations connecting the kernel and the spectral function for the characteristic operator of the linear multigroup transport theory are obtained. Decision problem of these systems is investigated.

ISSN:0041-1450    

DOI:10.1080/00411450008214531

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

By J.L. Heilbron Harvard University Press, 1999. 366 pages, $35

ISSN:0041-1450    

DOI:10.1080/00411450008214532

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor