摘要:

AbstractWe develop a new method for the efficient calculation of solenoidal vector fields on general regions. The method takes advantage of fast direct methods and uses boundary integral equations to satisfy boundary conditions. For the latter we give an effective scheme for computing far‐field boundary influences (based on discrete charges). Examples and numerical results are given. The method is applicable to incompressible Navier‐Stokes calculati

ISSN:0271-2091    

DOI:10.1002/fld.1650050902

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA new scheme is applied for increasing the accuracy of the penalty finite element method for incompressible flow by systematically varying from element to element the sign and magnitude of the penalty parameter λ, which enters through ∇.v +p/λ = 0, an approximation to the incompressibility constraint. Not only is the error in this approximation reduced beyond that achievable with a constant λ, but also digital truncation error is lowered when it is aggravated by large variations in element size, a critical problem when the discretization must resolve thin boundary layers. The magnitude of the penalty parameter can be chosen smaller than when λ is constant, which also reduces digital truncation error; hence a shorter word‐length computer is more likely to succeed. Error estimates of the method are reviewed. Boundary conditions which circumvent the hazards of aphysical pressure modes are catalogued for the finite element basis set chosen here. In order to compare performance, the variable penalty method is pitted against the conventional penalty method with constant λ in several Stokes flow case

ISSN:0271-2091    

DOI:10.1002/fld.1650050903

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe paper is concerned with stability and accuracy of annth order Lagrangian family of finite element steady‐state solutions of the diffusion‐convection equation, and furthermore is concerned with the stability and the accuracy of onmth kind Hermitian family of finite element solutions. We discuss the stability of the numerical solution based on the fact that the characteristic finite element solution can be expressed approximately as a rational function of cell Peclet numberPec( =uh/k). Moreover, it is shown that by eliminating derivatives and by using the interpolation method over elements a stable solution is obtained over the domain independent ofPecforP1,3, and forP2,5the stable solution is obtained forPecless than 4

ISSN:0271-2091    

DOI:10.1002/fld.1650050904

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe problem of computing the vibration modes of a structure vibrating in a fluid is examined with specific application to ship hulls. In particular, methods which take proper account of the three‐dimensional nature of the water movements are described. Fluid singularities involving either a line doublet on the intersection of the water surface with the plane of symmetry or distributed sources on retracted boundaries are particularly effective at modelling the fluid flow and appear to give better numerical efficiencies than finite element or boundary element methods. The effects of the extra coefficients in the mass matrix arising from added mass on the various methods of eigensolution are discusse

ISSN:0271-2091    

DOI:10.1002/fld.1650050905

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractModern lubricants often exhibit shear‐thinning due to the presence of high molecular weight polymers as additives. Therefore the influence of such non‐Newtonian effects on the performances of lubricating systems must be predicted. The corresponding fluid film flow is governed by a non‐linear partial differential equation, which generalizes the classical Reynolds equation. Having prescribed adequate boundary conditions, this equation is solved by a finite element method with optimal control. The problem of the square slider bearing lubricated by the Rabinowitsch fluid is solved in order to test the accuracy of the numerical scheme. The pressure and velocity fields are given and compared with the corresponding ones obtained for the Newtonian

ISSN:0271-2091    

DOI:10.1002/fld.1650050906

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050907

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050901

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY