摘要:

AbstractIt is shown that codes employing boundary‐fitted grids (BFG) in heat conduction problems involving heat sources must be implemented in strictly numerically conservative form if accurate results are to be obtained. It is demonstrated that, for one‐dimensional problems, non‐conservative form imply errors originated in grid non‐uniformity that cause a spurious increase in the heat source. This in turn leads to significant errors in the computed soution. Therefore the implementation of BFG codes using non‐conservative forms should be avoided. An application to an unsteady, axisymmetric benchmark problem involving a spherical, time‐decaying heat source i

ISSN:0748-8025    

DOI:10.1002/cnm.1630050102

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe boundary element method (BEM) provides a straightfoward mechanism for calculating interior values once the appropriate boundary values have been determined. However, the interior solution near the boundary can exhibit unusual behaviour resulting in large numerical inaccuracies. This ‘boundary layer’ effect has been noted but is largely unexplored in the BEM literature. In this paper the numerical inaccuracies are shown to stem from the inability of the quadrature to account for the Green's function near‐singularity. A simple scheme, which adds little extra computational effort, is used to remove the numerical inaccuracies at interior points close to the boundary by increasing the quadrature in the nearby boundary ele

ISSN:0748-8025    

DOI:10.1002/cnm.1630050103

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper presents a method for computing the electrostatic field distribution at the interface between two dissimilar dielectrics based on the least‐squares smoothing technique along with the potential‐based classical finite element method by suitably incorporating the interface nodal conditions. It is found to give accurate results when compared with the results obtained by classical finite element method, and also it gives the continuous field distribution at the nodes in the case of a homogeneous dielectric problem. By using this method, the electrostatic field distributions in a solid insulated single‐core cable with homogeneous dielectric and in a compressed sulphur hexafluoride (SF6) gas insulated disk‐type spacer cable are determined. Laboratory investigations have also been carried out on a disk‐type spacer cable by varying parameters like the spacer contact angle, the relative permittivity of the spacer material and the conductor

ISSN:0748-8025    

DOI:10.1002/cnm.1630050104

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630050105

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA direct solution procedure for computing the flutter Mach number and the flutter frequency is applied to the aeroelastic analysis of propfans using a finite element structural model and an unsteady aerodynamic model based on a three‐dimensional subsonic compressible lifting surface theory. An approximation to the Jacobian matrix that improves the efficiency of the iterative process is presented. The Jacobian matrix is indirectly approximated from approximate derivatives of the flutter matrix, which are updated only in the direction of the last move. Examples are used to illustrate the convergence properties. The direct solution procedure facilitates the automated flutter analysis in addition to contributing to the efficient use of computer time as well as the analyst's tim

ISSN:0748-8025    

DOI:10.1002/cnm.1630050106

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe central difference algorithm is a simple but effective time integration algorithm suitable for parallel processing. This paper discusses the development and implementation of the method for the fully nonlinear, transient dynamic analysis of three‐dimensional framed structures. A data structure is presented in which only one nearest‐neighbour communication is required per timestep, and potentially little overhead is incurred for the parallel implementation. Because this explicit method is only conditionally stable, the large disparity of natural vibrational frequencies of frame structures indicates that central difference analysis is most useful for applications having short‐duration loading. An example is presented indicating the speed‐up and efficiency of the algorithm when implemented in a distributed‐memory, coarse‐grained parallel processing

ISSN:0748-8025    

DOI:10.1002/cnm.1630050107

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA family of predictor‐corrector methods is used in PECE mode to obtain a numerical solution of a nonlinear second‐order hyperbolic partial differential equation. One particular predictor‐corrector combination is used to solve a problem from the liter

ISSN:0748-8025    

DOI:10.1002/cnm.1630050108

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA simple method for analysing laterally loaded piles is to consider the problem as a beam on an elastic foundation. In this representation, the finite element method is used to solve the governing differential equation, in preference to the more popular finite difference approaches. The pile is modelled using beam elements, and two different methods are compared for introducing the soil stiffness. The ‘consistent’ approach, where the governing differential equation is discretized using a Galerkin formulation, is shown to be considerably more accurate than a ‘lumped’ approach. The improvement is particularly noticeable when the finite element discretization becomes coarser. Some examples are presented to illustrate the differences, and comparisons are made with closed‐form

ISSN:0748-8025    

DOI:10.1002/cnm.1630050109

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630050111

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0748-8025    

DOI:10.1002/cnm.1630050112

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY