overview and summary of the third aiaa high lift ... · overview and summary of the third aiaa high...

OverviewandSummaryoftheThirdAIAAHighLiftPredictionWorkshop

ChristopherL.RumseyNASALangleyResearchCenter

Hampton,VA

JeffreyP.SlotnickTheBoeingCompany

Seattle,WA

AnthonyJ.SclafaniTheBoeingCompany

LongBeach,CA

AIAASciTech,Kissimmee,FL,January8-12,2018 1

Overview• GeneralsummaryofHiLiftPW-3results.• CFDcomparisonsagainstitself(consistency,verification).• CFDcomparisonsagainstexperiment(validation).

• HavethingsimprovedsinceHiLiftPW-2?• Whathavewelearned?• WhatshouldbedonedifferentlyforHiLiftPW-4?


Outline• Introduction• Highliftgeometriesandexperimentaldata• Gridsystems• Summaryofentries• Results• Turbulencemodelingverification• HL-CRM• JSM

• Statisticalanalysis• Conclusions


Wherewe’vebeen(somehighlights)• HiLiftPW-1(2010).• NASATrapezoidalWing-Body;includingeffectofflapdeflection.• CFDtendedtounderpredict lift;bigspreadnearstall.• NosupportbracketswereincludedintheCFD(whentheywere,predictedliftwasevenlower).• Transitionmodelingseemedtohelpimprovecomparisonswithexperiment.• Flownearwingtipwasverydifficulttopredict.


Wherewe’vebeen(somehighlights)• HiLiftPW-2(2013).

• DLR-F11Wing-Body;includingeffectofReynoldsnumber.• CFDsometimesunderpredicted,sometimesoverpredicted lift;againshowedbiggerspreadnearstall.

• Separationbehindslattrackswasprobablyinfluentialininitiatingstall;evenwhenincludingbrackets,CFDusuallygotitwrong(e.g.,separationbehindwrongbrackets).

• Nocleartrendswithtransitionmodelingstoodout.• Attainingsteady-stateconvergencesometimesdifficult.• ExperimentaloilflowswereextremelyusefulfordeterminingwhetherCFDwascapturingthephysicscorrectlyornot.


Quickcomparison


HiLiftPW-1 HiLiftPW-2 HiLiftPW-3

37submissions 48submissions 79submissions

HiLiftPW-3geometriesandexperimentaldata


HL-CRM JSM

NotyetbuiltTestedinJAXA-LWT1inearly2000s- Notripping

ForcesMomentCpOilflowSometransitioninfo

HiLiftPW-3geometriesandexperimentaldata


HL-CRM JSM

NotyetbuiltTestedinJAXA-LWT1inearly2000s- Notripping

ForcesMomentCpOilflowSometransitioninfoHiLiftPW-3alsopartnered

with thefirstGeometryandMeshGenerationWorkshop(GMGW-1),usingHL-CRM

Committee-providedgridsystems


Averagemedium grid:approx 71Mpointsand120McellsMedianmedium grid:approx 52Mpointsand107Mcells

ForHL-CRMandJSM

Summaryofentries• 35individuals/groupswith79entries.

• 14differentcountries(40%U.S.).• Broadrepresentationfromindustry,academia,CFDvendors,andgovernmentresearchlabs.

• Turbulencemodels:• MostusedSAorvariant(RC,R,neg,QCR,noft2).• K-omegatype:BSL,SST,SST-V,SST-V-sust,SST-2003,SSTwmods,Wilcox1988,Wilcox1988CC.• Lag-EB-ke.• SSG/LRR-RSM-w2012.

• Transitionmodels:• SST-gamma,AFT2017b,gamma-Ret-SST.

• Non-RANS:• FiniteelementwithimplicitSGSmodel.• LBwithVLESwallmodel.• LBwithWALESGSmodel.• DDES.

• Noteveryonesubmittedallrequestedcases.• Detailsinpaper.


Results• Turbulencemodelingverification• HL-CRM• JSM




DSMA661(ModelA)airfoil,M=0.088,alpha=0deg,ReC=1.2million(JFM160:155-179,1985)

Turbulencemodelingverification


OnlycompletedforSAmodel(SA,SA-neg,SA-noft2)

Theimportantroleofverification

2-Dverificationcase

VERIF/2DANWcasefromTMRwebsite:https://turbmodels.larc.nasa.gov

VerificationremovesonepossiblesourceofCFDuncertainty,foragivenmodel.Othersources:grid(size,extent,adherencetogeometry),BCs,iterativeconvergence.


8differentcodesproducenearlyidenticalresultsforSAmodel(CFL3D,FUN3D,Kestrel/COFFE,CFD++,OVERFLOW,BCFD,TAU,andLAVA)

Approximately30% ofthecodesthatrantheverificationcasewerefullyverified fortheSAmodel

Additionalverificationexercisesstillneededforothermodels,includingSAvariants



Focusingononlyafewmainpointshere;furtherdetails(suchaseffectofflapgaptreatment)aregiveninthepaper

HL-CRMgridconvergence(allresults)


alpha=8deg. alpha=16deg.

DragandmomentshowninpaperNote:bluecurvesrepresentgrid-adaptionresults


2-DverificationcaseHL-CRM

SAmodelsonly

BluelinespassedtheverificationtestforSA





2-DverificationcaseHL-CRM

SAmodelsonly




BluelinespassedtheverificationtestforSA

HL-CRMvelocityprofiles


FLAP:x=1615,y=638 MAIN:x=1495,y=638



Focusingononlyafewmainpointshere;furtherdetailsaregiveninthepaper

JSM,nonacelle/pylon


Liftcoefficient Dragcoefficient Momentcoefficient

JSM,withnacelle/pylon



JSM,deltasbetweennacelle/pylononandoff



Exceptforoneoutlier,participantspredicteddeltaswell(albeitlargescatternearmaxlift)

CFDresultsthatagreed“best”withJSMCL data


Nonacelle/pylon Withnacelle/pylon

Minimize!"Σ 𝐶𝐿, 𝐶𝐹𝐷 − 𝐶𝐿, 𝑒𝑥𝑝

2

(ignoringresultswithno/lateCL,max)

SASALBVLESSASA-RC-QCRSA-RC-QCRW98CC+transLBWALESST[mod]

SA-QCRSA-negSA-negSA-RC-QCRSA-RC-QCRW98CCW98CC+transLBWALESST[mod]

Generalobservationfromtheworkshop• MostoftheRANScodesproducedsurfaceflowsthathadtoomuchseparationnearthewingtipcomparedtotheexperimentandnotenoughseparationnearthewingrootatandbeyondmaxlift.• Notableexceptions:scale-resolvingmethods(likeLB).


Exp,alpha=18.58deg. Exp,alpha=21.57deg.

Generalobservationfromtheworkshop• MostoftheRANScodesproducedsurfaceflowsthathadtoomuchseparationnearthewingtipcomparedtotheexperimentandnotenoughseparationnearthewingrootatandbeyondmaxlift.• Notableexceptions:scale-resolvingmethods(likeLB).


Exp,alpha=18.58deg. Exp,alpha=21.57deg.

(notionaltypicalRANS)

JSM:surfacepressurecoefficients


A-A B-B C-C

E-E G-G H-H

Mainelement,alpha=21.57deg.,nonacelle/pylon

JSM:issuesnearCL,max



GridandtemporaltreatmentbothhavebiginfluenceSamecode&model,differentgrid

Samecode&model,differentgridSamecode,model&grid,time-accuratevs.steady-state

JSM:furtherevidenceofinsufficientgriddensity


All“SA-verified”codesdonotagreewellusingSAon(different)mediumgrids

COFFE,gridC1TAU,gridBTAU,gridf(nc)OVERFLOW,gridATAU,gridBLAVA,gridAFUN3D,gridC1FUN3D,gridC2

Andbluecurvespointtominorissueswithinsufficientiterativeconvergenceand/orcodesetting/versiondifferences

JSM:effectoftransitionmodels



• TransitiondefinitelypresentatthisRe• For030.1vs.030.3(committeegridE),littleinfluenceoftransitionnoted• For030.2vs.030.4(participantgridb),transitioncausedhigherCL inthe

linearrangeandanearlierstall,inbetteragreementwithexperiment

SST-gammaSA-RC-QCR+AFT2017bW98CC+transW98CC+trans

SA-RC-QCR+AFT2017bW98CC+trans

Statisticalanalysis:HL-CRM• Mainconclusion:generalscatterdidnotalwaysdecreasebetweenthemediumandfinegrids,aswouldbeexpectedifnumericalerrorduetogridresolutionwastheprimarysourceofvariation.


Notch=medianDiamond=mean

Upperandlowerquartiles

Minvaluethatisconsideredstatisticallysignificant

OutlierShadingrepresentsdistribution

Statisticalanalysis:JSM


alpha=4.36deg. alpha=14.54deg. alpha=20.59deg.

Cv=σ/𝜇 =standarddeviation/medianScatterlimits=µ ± 𝐾𝜎(𝐾 = 3� )

Focusingononlyafewmainpointshere;furtherdetailsaregiveninthepaper

HasCFDgottenanytightersinceHiLiftPW-2?

Cases Cv,lowalpha Cv,midalpha Cv,highalpha

HiLiftPW-2,alpha=7,16,20deg.

0.038 0.057 0.060

HiLiftPW-3, alpha=4.36,14.54,20.59deg.

0.025 0.017 0.073


LowRe,withbrackets,mediumgrids

YES YES NO

Conclusions• Intheverificationcase,only30%oftheCFDcodesthatparticipatedwiththeSAturbulencemodelwerefullyverified.• HL-CRMcaseexploredgridconvergence.

• SpreadbetweenCFDresultsdidnotdiminishonfinegrids(similartoHiLiftPW-2).• Lackofverificationinsomecodesmayexplainpartofthespread.

• JSMexploredeffectofnacelle/pyloninstallation.• Useof“medium”gridonly;deltasweregenerallywellpredicted.• LargespreadinCFDresultsnearCL,max (similartoHiLiftPW-1and2).• SignificantinfluenceofgridnearCL,max,so”medium”gridprobablynotfineenough.• Transitionshouldbeimportantforthiscase,buttransitionmodelswerenotalwaysbetter(gridinfluence?).

• Manyindividualresultscomparedverywellwithexperimentalliftcurve;butwedonotknowwhy.

• Itwaspossibletogetintegratedquantitiesrightforthewrongreasons.• Scale-resolvingmethodsappearedtopredictseparationpatternsbetterthanRANS.• Participantsweremoreconsistent(comparedtoHiLiftPW-2)predictingcomplexhigh-liftconfigurationatlowRewithallmountingbrackethardwareatlowalphas– BUTNOTNEARCL,max.


HiLiftPW-4statusandotherquestions/thoughts• WhatshouldbedonedifferentlyinHiLiftPW-4,sothatwelearnmore?• Proposal:requiretheuseofoneormorespecific(verified)models.

• Identifythe“best”(publicly-available)RANSmodel(s)fromthisworkshop,andrequestthatallRANSparticipantsverifyit intheircodeanduseit.

• Allowadditionalresultsusinganymodelormodelvariant.• NearCL,max: encouragelargergrids,moregridadaption,higherorder,time-accurate,moreuseofscale-resolvingmethods.• Nomorefree-airCFDruns;trytomatchthewindtunnelsemispan testinggeometryandBCs.


End


Backup


Introduction• Specificworkshopseriesfocusedonthepredictionofswept,medium/high-aspectratiowingsinlanding/takeoff(highlift)configurations.• GoalsofHiLift workshopseries:• Assessthenumericalpredictioncapability ofcurrent-generationCFDtechnology.• DeveloppracticalmodelingguidelinesforCFDpredictionofhighliftflowfields.• Advancetheunderstandingofhighliftflowphysicstoenabledevelopmentofmoreaccuratepredictionmethodsandtools.• EnhanceCFDpredictioncapabilityforhighliftaerodynamicdesignandoptimization.• Provideanimpartialforum.• Identifyareasneedingadditionalresearchanddevelopment.


Testcases• Case1- GridConvergenceStudyontheNASAHL-CRM(freeair,fullyturb).

• 1a:Fullchordflapgap,M=0.2,ReMAC=3.26M,alpha=8,16deg.• 1b:Sameas1a,withgridadaption.• 1c:Sameas1aexceptpartially-sealedflapgap.• 1d:Sameas1c,withgridadaption.

• Case2- NacelleInstallationStudyontheJSM(freeair,fullyturb orwithtransition).• 2a:Nacelle/pylonoff,M=0.173,ReMAC=1.93M,sixalphas.• 2b:Sameas2a,withgridadaption.• 2c:Sameas2aexceptNacelle/pylonon.• 2d:Sameas2c,withgridadaption.

• Case3- TurbulenceModelVerificationStudy(fullyturb).• VERIF/2DANWfromhttp://turbmodels.larc.nasa.gov


Black=requestedBlue=optional

Gridsystems

Label Gridtool Org Type Coarse Medium Fine Extra-fine Notes

A-HLCRM ANSA+Chimera

NASA str 24/23 65/64 189/185 564/554 Overset

B1-HLCRM Pointwise Pointwise unstr 8/48 26/157 70/416 206/1228 Tet

B2-HLCRM Pointwise Pointwise unstr 8/22 26/65 70/170 206/541 Mixedprism/tet

B3-HLCRM Pointwise Pointwise unstr 8/18 27/48 71/119 208/397 Mixed

C-HLCRM GridPro GridPro str 10/8 77/68 338/311 n/a One-to-one


HL-CRM“committeegrids”

Points/cells

Gridsystems

Label Gridtool Org Type Medium,noN/P

Medium,with N/P

Notes

A-JSM Chimera NASA str 221/216 235/230 Overset

B-JSM DLR-SOLAR DLR unstr 102/162 126/207 Mixed

C1-JSM VGRID Spaceship&Gulfstream

unstr 16/97 21/124 Tet

C1-JSM VGRID Spaceship&Gulfstream

unstr 16/52 21/65 Mixed

D-JSM JAXAtools JAXA unstr 50/120 59/139 Mixed

E-JSM ANSA UOxford&BETA-CAE

unstr 52/107 58/120 Mixed


JSM“committeegrids”

overview and summary of the third aiaa high lift ... · overview and summary of the third aiaa high...

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