摘要:

AbstractThe diffusion of the particles is described in terms of a mean motion with a speed equal to the osmotic velocity associated with the diffusion process. Three numerical schemes are presented. The first two are based on the approximation of the gradient on an irregular mesh. The third is derived from a finite‐element approach. Voronoi diagrams are used to handle the irregular grid of the particles. The convergence of the schemes is studied numerically, by comparing the results with the exact solution. Applications to the Fokker‐Planck equation and to the problem of disposing particles according to a given probability distribution are presen

ISSN:0010-3640    

DOI:10.1002/cpa.3160430602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractA grid free Lagrangian finite element method is introduced for the 2‐D incompressible Euler equations. The method is derived based on the observation that the product of the Biot‐Savart kernel and a polynomial can be integrated analytically over any triangle. This enables us to obtain a numerically stable Lagrangian method without using numerical smoothing. Moreover, we show that the method converges uniformly with second‐order accuracy. Actually, we establish al∞stability result which applies to kernels that are more singular than the Biot‐Savart kernel, as long as the kernel isL loc1integrable. Another useful result is that we prove convergence of our method when using local regridding, which allows the method to run for longer time even with a fixed mesh. The second‐order convergence is also illustrated by our numerica

ISSN:0010-3640    

DOI:10.1002/cpa.3160430603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractWe are concerned with the estimation of the effective electrical conductivity of random heterogenous materials. The purpose of this paper is to discuss a property of “statistical symmetry” verified by the symmetric cell materials of Miller. This property will be referred to as infinite interchangeability.The usual way to approach cell materials is throughn‐point correlation functions. The property of infinite interchangebility permits us to approach cell materials from a completely different point of view. Our main result is a simple algorithm, based on this symmetry property, for computing any coefficient of the perturbation expansion in terms of information from the dilute limit. Specifically, knowledge of the coefficients of the expansion in powers of the volume fraction up to orderrallows for computation of the perturbation expansion coefficients up to order (2r+ 1). This result, which was previously known forr= 2 in the isotropic case and forr= 1 in the anisotropic case, can also be obtained from the standard correlation function approach, as pointed out by M

ISSN:0010-3640    

DOI:10.1002/cpa.3160430604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

ISSN:0010-3640    

DOI:10.1002/cpa.3160430605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

ISSN:0010-3640    

DOI:10.1002/cpa.3160430601

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY