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Based on Object Orientation

Takahiro Ueda

Scho ol of Information Science,

Japan Advanced Institute of Science and Technology

February 14, 1997

Keywords: object orientation,classs,object,attribute,metho d.

Abstract

A Background and Purpose

It will require a great deal of labor to write a program for a computer to solve some

complicated ow,such as ow with complicated shape,ow with heat transfer.In spite of

the above eort,theconstructed program isno use againstthe extension toappliedsome

other analysis of problems.Whether we can trust insimulation or not wecannot still es-

tablish. To nd a way of the above problems the simulation on object orientaion have

been studying.But no excellent resultshaveobtained yet.

Thetheoryofthenitedierenceequationsonobject-orientedmethodologyisprop osed

by Hatakeyamaandothers.Butthelinestosolvesomecomplicatedow,withcomplicated

shape,withheat transfer,e.t.c. are not laied down.

This paper describes the studyof numerical simulation based on object orientation.In

this study,forthepurposeof solvingthe aboveproblems theobject-orientedconception is

intro duced for the exible and accuracy mo deling.Consequently,it is demonstrated that

the prop osed model are more exible and higher trusted than the past model.

Modeling System

First,we set grid p oint at innitesimal volume object and we simulated heat transfer

problem of Poisson equation inthis model.It is conrms that the model onobjectorien-

tation can be used insimulation.

Copyright c

1997byTakahiroUeda

equation in MAC(Markerand Cell) Method into class metho d. Supp erclass,that is, grid

objectclassleadsub class,herepressureclass,velocityclasstoitsclassinrelationtophysi-

cal. Subclassinheritesomespecial property suchasclass,attribute,methodtoSuperclass.

This object model is extended to the model to be able to treat heat transfer prob-

lem.temperaure object class is added to the object model. In this step,the problem

that proposed model can hardly deal with some ow with complicated shape.In addi-

tion,generally there is one problem that execution time is late as grid object numb er

increase.

we try to improve model more exible and eciency with the intension of applica-

tion in complicated ow and getting high performance to parallel calculation. For the

reason,the domain in original target world is setted at the domain object.The relation

between grid object and domain object isaggregate.Using this mo del in connectionwith

module,itisexpectedthattheinnercompicatedmanagementishiddenunderinformation

hiding eect, that is,the complicatedmanagementis diminished toa minimum.

Result

Obtained result inthis studyis describedin that follow intermittently.

(1) Constraction of muchhigher reliable mo del by inducing some subclass from super-

class,grid class in relationto physical

(2) Flexibleextension of the abovemodel in the problem heat accompanied

(3) Much higher reliance of extended model compared with the past mo del to receive

b enet of reuse fromthe abovemo del

(4) Reducing of complicated management by information hiding eect to aggregate

b etween domainclass and grid class

(5) Flexible modication to ow with complicated shape to take some domain object

instance.

(6) Possibleexecutionoflocalheatingondomainobjectinrelationtothe abovemo del

(7) Possibilityofparallelcalculationtoasignoneorsomedomainobjecttooneprocessor

It is mensioned from result(1) that the mo deling of object model with discretized

equation of MAC Method is performed in subdivision.Accordingly, the prop osed model

hardly make a mistake againt the past model do something,such as a physical variable

calls no-usedfunction.

Proposed object model by Hatakeyama and others includes all physical attribute in

grid class.it is conrms our model has higher reliable.Further,it is suggested about brief

extension of 3D problem.

heat transfer is given.

Inconnectiontotheresult(2),theresult(3)saysthattheextensionobjectmodelreceive

benet ofreuse from the basedmodel.Thisis aconsequence that objectoriented merit is

used eectively.

Fromtheresult(4), itissuggested thatthetroubleinop eration oflinkbetweenobjects

savedto acertain extent.

Itismentionedfromtheresult(5)thatowwithcomplicatedshapeiseasiersimulation

to communicateb etween domainobjects.

Fromtheresult(6),sincedomainmodelincludestheconceptionofgridobjectmodel,ow

is included eect of heat transfer,is shown.

It is mentioned from result(7) that parallel calculation to asign one or some domain

objectto one pro cessor would be performed easier.

The proposeddomainobjectmodel isaddedmeritbyitselftotheadvantagewithgrid

object.Consequently,the proposed modeling in this study have demonstrated have much

higher reliance and much exible compared with the past model used nite dierence

method.

Inthisstudy,theproblem,thatis,owanalysiswithcomplicated,programing,allmanner

of problem in relation to porgram modication or extension e.t.c.,is improved consider-

ably.It is thought that the approach which we change basic mo del to extend model is

proposed.

Problem to be solved

This studyprop osed exible and higher reliablemodel. But diculty maybeoccured

to simulate ow with movement boundary or compressible ow. Another mo deling or

considerable object getting will be nesessary to that solution.Parallelcalculation will be

also to o.