Accession Number : ADA131279

Title :   Moving Finite Elements in 2-D.

Descriptive Note : Annual rept. no. 2, 8 Jun 82-7 Jun 83,

Corporate Author : SCIENCE APPLICATIONS INC PLEASANTON CALIF

Personal Author(s) : Gelinas,Robert J

PDF Url : ADA131279

Report Date : 03 May 1983

Pagination or Media Count : 28

Abstract : In this second year of effort, truly large-scale computing aspects of PDE's (partial differential equations) have been addressed. MFE (moving finite element) node movement properties of highly sheared fluid flows and shocks were studied. The following results were obtained: (1) extremely large nodal savings were obtained by the MFE method in highly sheared shock examples; (2) such ODE solvers as the Gear method require significant restructuring of their internal code logic in order to achieve improved time step and error-controlling policies in PDE applications; (3) iterative linear solvers are required in order to accommodate large MFE grid meshes; (4) a new iterative solver of linear systems was developed in order to attain large convergence rates in advection-diffusion equations with highly inhomogeneous mesh spacings, which cannot be solved satisfactorily with other existing linear solvers; (5) first-generation regularization schemes resolved highly sheared flows; and, although large grid aspect ratios were resolved successfully, new regularization functions which homogenize MFE grid cells should be developed in future work; and (6) singularities which are frequently troublesome in cylindrical and spherical co-ordinates are eliminated naturally in MFE inner product formulations. (Author)

Descriptors :   *Finite element analysis, *Two dimensional, Computations, Partial differential equations, Problem solving, Fluid flow, Gradients, Iterations, Moving targets, Linear systems, Grids, Mesh

Subject Categories : Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE