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NASA

Contractor

ICASE

Report

Report No.

182040

90-35

ICASE FOURIER ANALYSIS OF FINITE ELEMENT PRECONDITIONED COLLOCATION SCHEMES

Michel O. Deville Ernest H. Mund

Contract May

No.

NAS1-18605

1990

Institute NASA Hampton, Operated

for Computer Langley

Applications

Research

Virginia

in Science

and Engineering

Center

23665-5225

by the Universities

Space

Research

Association

IW A National Aeronaulics and Space Administralion Langley Research Center Hamplon, Virginia 23665-5225 (NA_A-C_-132060) FFIUPIE:_ ANALYSIS ELEMENT PR_CONOTIIONZD COLLOCATTLI (TEA3 c ) 25 p

N90-Z3128

OF FINITE _'-jSCHEMES CSCL 12A

Uncl,as

Ri

G3/64

0280814

!

FOURIER

ANALYSIS

OF

PRECONDITIONED

FINITE

ELEMENT

COLLOCATION

Michel Universit6 Unit6

SCHEMES

O. Deville t

Catholique

de Louvain

de Mdcanique

Appllqude

Louvain-La-Neuve,

Belgium

and Ernest Universitd Service

H. Mund

Libre

de Bruxelles

de Mdtrologie BruxeUes,

Nucldaire

Belgium and

Universit6 Unitd

Catholique

de Louvain

de Thermodynamique

et Turbomachines

Louvain-La-Neuve,

Belgium

ABSTRACT This

p_per

investigates

conditioned

Fourier

elliptic

hyperbolic

and

pressions part

of the

of the

Fourier previous

model

considers (in the

conclusions

spectrum

collocation

eigenvalues

paper

analysis

the

schemes_

The

problems are the

tranverse

on the

of the iteration and

obtained

first the

with

part

operator of the paper

use

of symbolic

numerical

differential

of the 2-D Stokes

efficiency

of finite

element

pre-

one-dimensional

equation.

Analytical

computation. equations

problem.

element

finite

analyses

advection-diffusion

set of one-dimensional direction)

of some

The

second

resulting

All results

preconditioning

ex-

agree

from with

schemes.

IThls researchwas supported by the National Aeronautics and Space Administration under NASA Contract No. NAS1-18605 while the author waz in residenceat the Institutefor Computer Applications in Science and Engineering (ICASE), NASA

Langley Research Center, Hampton, VA 23665.

1.

INTRODUCTION In the recent

past,

Chebyshev

collocation

schemes

have

been

applied

extensively

to the

numerical integration of the Navier-Stokes equations [1, 3, 4]. For scalar is well known that the condition number of the matrix system of discrete

elliptic problems, it algebraic equations

increases

at hand.

the

rapidly

with N, the number

preconditioning

this numerical

technique

burden.

constitute powerful fluid flow elements

of degrees

seems

The

present

the

authors

preconditioning

numerically,

were sake

preconditioned algebra

of simplicity, Fourier

process

elements,

collocation

of the eigenvectors analyses consists

that

finite

Therefore, to overcome

elements

(FE)

numerical

the

aims

perform

as preconditioners. carried

element

is uniform

and

is considered. cubic

is set Using

4, the Fourier

out in the framework

numerical

using linear A further

problem is done.

and

model

is reduced

The Q2-Q1

analysis

FE

of the eigenvalues

is investigated Stokes

Hcrrnite structure

the previous

discretization.

the The

these

the spatial

is also examined.

In Section

and

up with

a full analysis

model

technique

A similar

of a finite

size

corroborates

hyperbolic

to Fourier

results

quadratic,

solvers.

investigation

equation.

analytical

model

method

algebraic

one may

at

study

mesh

linear,

iteration

and

amenable

experiments

note to the

case,

Lagrangian

The upwinding

flow model

the Q2-Q1 element is the analyses on finite element

2, a one-dimensional

3, a one-dimensional

are candidates

corroborate

In this

solutions,

in an advection-difI_usion

a 1-D incompressible

by

This theoretical

FE preconditioning.

elements

in order

[10]).

ourselves

Richardson

operators

of the Fourier

[6]. In Section

quadratic

The

present

(cfr.

restrict

In Section

is preconditioned

operator.

the

scheme.

reduced.

as approximate

iteration

tool

it was shown that As all the previous

languages

we will

respectively.

preconditioners of the

out

manipulation

is considerably

collocation cubic

carried

use of symbolic the

of the problem adequate

preconditioners for general second-order elliptic equations. In [3], several in velocity-pressure formulation were investigated. From the analysis of operator, problem.

For

only

[5, 6] demonstrated

the eigenspectrum of the iteration best choice for the steady Stokes through

of freedom

to be

and

to

Q1-P0

The results

of Chebyshev

collocation

[3]. 2.

ELLIPTIC Let us first

MODEL consider

the

simple

elliptic

problem:

=/, with periodic boundary

0 _<x _


c_

9.9.

r

Report 5_clce/_,Orn,n,

1. Repo_

2. Government

No,

NASA

Page

Accession

No.

3. Recipient's

Catalog

No.

CR-182040

ICASE 4. Title

Documentation

SIralOn

Report

No.

90-35

and Subtitle

5. Report

FOURIER ANALYSIS OF COLLOCATION SCHEMES

FINITE

ELEMENT

May

PRECONDITIONED

7. Author(s)

Michel Ernest

Date

1990

6. Performing

Organization

Code

8. Performing

Organization

Report

No.

90-35

O. Deville H. Mund

10. Work

Unit

No.

505-90-21-01 9. Performing

Organization

Name

and Addre_

Institute for Computer Applications in Science and Engineering Mail Stop 132C, NASA Langley Research Center Hampton, VA 23665-5225 12. Sponsoring

Agency

National Langley Hampton,

or Grant

13.

Ty_

of ReportandPeriodCover_

Contractor Space

No.

NASI-18605

and Address

Aeronautics and Research Center VA 23665-5225

15. Supplementaw

Langley Richard

Name

11. Contract

Report

Administration 14. Sponsoring

,_gency

Code

Notes

Submitted Scientific

Technical Monitor: W. Barnwell

to SIAM Journal and Statistical

on

Computing Final

Report

16. Abstract

This paper investigates the spectrum of the iteration operator of some finite element preconditioned Fourier collocation schemes. The first part of the paper analyses one-dimensional elliptic and hyperbolic model problems and the advectiondiffusion equation. Analytical expressions of the eigenvalues are obtained with use of symbolic computation. The second part of the paper considers the set of one-dimensional differential tranverse direction) of the conclusions on the numerical

equations 2-D Stokes efficiency

resulting from Fourier analysis (in the problem. All results agree with previous of finite element preconditioning schemes.

18. Distribution

17. Key Words(SuggestedbyAuthor(s))

finite element, collocation method, eigenvalue analysis, spectral methods

Statement

54 - Numerical Analysis 34 - Fluid Mechanics and

Unclassified 19. SecuriW

Cla_if.

(of this report)

Unclassified

NASA

FORM

_.

SecuriW

Cla_if.

UnClassified

(of this page)

Heat

Transfer

- Unlimited 21. No.

24

of pages

22. Price

A0 3

1626 OCT 86

NASA-La_Iey,

1990