Mpcci学习Word格式.docx

Mpcci学习Word格式.docx

《Mpcci学习Word格式.docx》由会员分享，可在线阅读，更多相关《Mpcci学习Word格式.docx（98页珍藏版）》请在冰豆网上搜索。

xxx*timestepsize与abaqus>

Basic>

Timeperiod相同。

？

Whenyoucreateacoupledsimulationproject,theMpCCIGUIgeneratesasetoffilescontainingthedefinitionofthecoupledsimulationmodel,e.g.theMpCCIinputfileandtheMpCCIlogfiles.Consequently,beforeyoustarttheMpCCIGUI,youshouldmovetoadirectorywhereyouhavepermissiontocreatefiles.

YouexecuteMpCCIGUIbyrunningthempcciexecutablewiththeguisubcommandandthedesiredoptions.

Mpccigui[OPTIONS][project][OPTIONS]

Options:

-chwd<

PATH>

Replacethesymbolicworkingdirectory$（CWD）

usedinsidetheprojectfilebytheabsolute

pathnamespecifiedinthe<

argument.

-newStarttheGUIwithanewproject.

BeforestartingacoupledsimulationyouhavetoestablishaprojectbyusingtheactionSaveAsfromtheFilemenu.

[开始模拟前，使用Filemenu中的Saveas创建project。

Projectfile产生inputfile，同时包含在MpCCIGUI中设置。

]

File>

SaveProjectAssavestheprojectsettingsunderaspeci_edname.TheMpCCIGUIdisplaystheSave

Asdialogbox.Theactiveprojectcanberenamedandsavedtoanewdirectory.

TostartanMpCCIjobinbatchmodewithawellpreparedcoupledsimulationprojectuse:

mpcci-batch<

projectname>

IfyoustarttheMpCCIGUIwithoutanyoptionslike

mpccigui

thefollowingdefaultchecksareperformed:

_Checkandpreparationofyourenvironment.

_Acheckofyoursecureshellrsa/dsakeyfiles.Ifnorsa/dsakeyfilesarefoundyouwillbeaskedtocreatethem.

_CheckforanexistingprojectfileinthecurrentdirectoryinordertoloadthatprojecttotheMpCCIGUI.Ifmorethanoneprojectfileexistsnoprojectwillbeloaded.

_Checkofthelicenseenvironment.MpCCIGUItriestocheckforalicensee.g.MPCCILICENSEFILEandalsoinformsyouwhenyourlicensewillsoonexpire.Inordertodisableitusetheoption-nolic.

Ifyoudonotincludethe<

tothempcciguitheMpCCIGUIstartsattheinitialstep.

CouplingStep

usageofthesamemodeldimensionbythecoupledcodes.

usageofappropriatesolutiontypesbythecoupledcodes.Thesolutiontypeswillbefoundbythescannerandmaybestatic,transientorundefined.Differenttypesinthemodelfilesleadtoawarningmessage.Undefinedtypesaretreatedasbeingproper.

MpCCI名字

物理含义

DeltaTime

时间步长

AbsPressure

绝对压力

OverPressure

相对压力prel=pabs–pref

WallForce

壁面力（absolutepressure+friction）

RelWallForce

相对壁面力（relativepressure+friction）

NPosition

节点位置

NDisplacement

节点位移

WallHTCoeff

换热系数

FilmTemp

薄膜温度

WallTemp

壁面温度

WallHeatFlux

壁面热流

LorentzForce

Lorentz力密度向量

JouleHeat

体积Joule热密度

初始的交换

“initialquantitiestransfer”能设置成以下四种:

▪“send”

-第一次交换中只发送数据

▪“receive”

-第一次交换只接受数据（程序等待数据）【abaqus用】[相当于此时接收到fluent的载荷]【在求解前交换】

▪“exchange”

-发送数据,然后程序等待接受数据【Fluent用】[相当于此时fluent先计算然后输出pressure或friction的载荷到abaqus，然后等待abaqus返回Nposition]【在求解后交换】

▪“skip”（or“none”）

-第一次交换没有动作

耦合算法的结构

第一步:

▪首先检查在求解前或求解后是否交换

例子:

▪程序A在求解后交换

▪程序B在求解前交换

▪起始交换:

-程序A:

exchange

-程序B:

receive

时间步上求解

操作次序:

▪程序A开始计算

（1）

▪程序B等待数据

▪程序A结束计算并发送数据

（2）

▪程序A等待数据

▪程序B获得数据并计算（3）

▪程序B发送数据（4）

▪程序A计算（5）

▪程序A发送（6）

▪程序B继续（7）

Typicalmulti-physicssimulationsare:

Fluid-StructureInteraction（FSI）:

Firstsystem:

Fluidow（Navier-Stokesequations）

Secondsystem:

Solidmechanics（equilibrium）

Quantities:

Pressure（1>

2）,deformation（2>

1）

Thermomechanicalcoupling

Heatconduction（Fourier'

slaw）

Temperature（2>

1）,deformation（1>

2）

Electrothermalcoupling

Electricalconduction（Maxwell'

sequations）

Temperature/electricconductivity（2>

1）,powerloss/Jouleheat（1>

2）

Tofindasolutionforacoupledproblem,allgoverningequations,whichcanbecombinedinalargesystem,mustbesolved.Thesolutioninthiswayiscalledstrongcoupling.However,solvingasystemwithstrongcouplingisoftendifficultasdifferentapproachesarenecessarytosolvethesub-problems.

Analternativeapproachisthroughweakcoupling.Hereeachproblemissolvedseparatelyandsomevariablesareexchangedandinsertedintotheequationsoftheotherproblem.Thisprocedureusuallyyieldsalessexactsolutioncomparedtostrongcoupling.Theadvantagesoftheweakcouplingarethatthesub-problemscanbesolvedfasterthanthecompletesystemandthatspecializedsolverscanbeusedforeach.

Figure2:

Staggeredalgorithmforsolutionofacoupledproblem.

ThestaggeredmethodissketchedinFigure2,whichisoneoftheweakcouplingapproachesofMpCCI:

CodeAcomputesonestep,sendsdatatocodeB,whichthencomputesonestepandsendsdatabacktocodeAandsoon.Inadditiontothestaggeredapproach,MpCCIsupportsparallelexecutionofbothcodes.Theselectionofthecouplingalgorithmisdescribedin.2.8GoStep{StartingServerandCodes/.

Animportantissueisthedataexchange.Thequantitiesmustbetransferredfromonecodetotheother.

Thisprocesscanbedividedintotwoparts:

Association:

Eachpointand/orelementofthecomponentsofacouplingregionislinkedtoapartnerintheothersystem.Theprocessoffindingpartnersisalsocalledneighborhoodsearch,see.V-3.3Data

Exchange/.

Interpolation:

Thequantitiesmustbetransferredtotheassociatedpartnerontheothermesh.Inthisprocess,thedifferentmeshgeometries,datadistributionsandtheconservationoffluxesmustbeconsidered.

MpCCIfullysupportsthedataexchangebetweennon-conformingmeshes,i.e.themeshesofeachsubsystemcanbedeffinedtooptimizethesolutionofthesubsystem.

Figure3:

Co-simulationwithMpCCI:

Overviewofthesimulationprocess

DefinitionoftheCouplingProcess.Simulationcodesandcorrespondingmodelfilesmustbeselected.Thecoupledregions,quantitiesandacouplingalgorithmmustbeselected,furthercouplingoptionscanbegiven.ThisstepiscompletelysupportedbytheMpCCIGUI.

RunningtheCo-simulation.AfterstartingtheMpCCIserver,bothcoupledcodesarestarted.EachcodecomputesitspartoftheproblemwhileMpCCIcontrolsthequantityexchange.

[先启动Mpcci，然后启动fluent及abaqus]

Post-Processing.Aftertheco-simulation,theresultscanbeanalyzedwiththepost-processingtoolsofeachsimulationcode,withtheMpCCIVisualizerorwithgeneral-purposepost-processingtools.【结果后处理可在fluent、abaqus、Mpccivisualizer中进行】

Asimpleexample

Figure1.Asimplecoupledsystem

ExchangeofquantitiesintheexampleFSIsimulation

2.2modelpreparation

Beforestartingthecoupledsimulation,themodelsmustbepreparedineachcode.Inourexample,thisrequiresamodeloftheflowregionandamodeloftheflapstructure.

Bothmodelsarecreatedintheundeformedcondition,i.e.theflapisstraight.ThecomputationofsuchaproblemrequiresaCFD-codewhichcanhandlemoving/deformablemeshes.[在fluent及abaqus中建立的模型都是没有发生变形]。

CFD软件必须能够处理moving/deformablemeshes.

ItisrecommendedthatyoukeepyourFEandCFDmodelfilesinseparatedirectories（seeFigure3）.

[推荐按figure3所示，将FE、CFD、Mpcci的文件保存在不同的路径下]

becauseofthefollowingreasons:

_Clearstorageandmaintenanceofsimulationdata.

_Ensuringthatthecodesdonotoverwritefilesofothercodes,whenidenticalfilenamesareused.

_Simplificationoftheportingoftheanalysiswhenrunningthesimulationondifferentplatforms.

Figure3.Organizationofthedirectories

2.2.1CFDModel

Figure4:

FluiddomainandCFDmesh

Tomodelthefluiddomain,definethegeometryintheCFDpre-processorandcreateamesh.

Allboundaryconditionsmustbedefinedaswell[如Figure4.中蓝色的线所示].Theycomprisetheflapsurface,walls,inletandoutletinFigure4.Alsoforthecouplingregionboundaryconditionsmaybeset-thisdependsontheCFDcodeapplied,pleasechecktheCodesManualfordetails.

Flapsurface是couplingregion，couplingregionboundaryconditions的设定随CFD软件而变化。

Itisrecommendedtorunthefluidproblemonitsownbeforestartingacoupledsimulationtobesurethatthemodelsetupiscorrect.Inthepresentexamplethecouplingregioncouldbedefinedasarigidwallforthispurpose.IfthemodelisnotappropriateforcomputationswiththeCFDcodealone,itismostlikelythataco-simulationwilleithernotrun.

在进行co-simulation之前必须进行单独的CFD计算，以保证CFD设置没有问题，能计算出结果。

此时可将couplingregion定义为rigidwall。

如果CFD无法计算出结果，co-simulation肯定没有结果。

2.2.2FEModel

ComparedtotheCFDmodelwhichcoversthefluiddomain,theFEmodelcoverstheflapitself.Figure5showsameshoftheflapwithquadrilateralelements.TheelementsizesdonotneedtocorrespondtothoseofthefluiddomaininanywayasMpCCIcanhandlenon-conformingmeshes.FEmodel仅包括flap本身，flap的element不需与fluiddomain相匹配，MpCCI能处理non-conformingmeshing.

Theflapisconnectedtothetopwall,i.e.thetopnodesofthemeshmustbefixed.[flap上端的单元node将被固定。

注意固定的是node]Thesurfaceoftheflapmustbedefinedasaboundarytowhichthepressureloadcanbeappliedintheco-simulation[flap表面将被定义为在co-simulation时可加载pressureload的boundary].Althoughthesystemwillnotshowanydeformationwithoutanexternalload,itisrecommendedtocheckthevalidityofthemeshandboundaryconditions（i.e.thefixednodeshere）byrunningtheFEproblemaloneand