nearfield summary and statistical analysis of the second ... · nearfield summary and statistical...
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NearfieldSummaryandStatisticalAnalysisoftheSecondAIAASonic
BoomPredictionWorkshop
MikeParkandMarianNemecComputationalAerosciences Branch
NASALangleyandAmesResearchCenters1
Motivation• Commercialsupersonicoverlandflightiscurrentlyprohibited– Supersonicoverlandflightisanenablerforentryintonewvehiclemarket
• Aninternationalefforttoquantifytheaccuracyandreliabilityofpredictionmethodssupportsthereplacementtheprohibitionwithacertificationstandard
• Deficienciesinexistingmethodsshouldbenotedtofocusresearchonaddressingweaknesses
2
Motivation• Nearfield CFDispartofsonicboomprediction
• Impartiallycomparesignaturesbyuniforminvestigationof– PropagationandLoudnessmeasures
– Gridrefinement– Statistics
3
ModelsandCases
• Designedtoproducesimilarsignatureswitharangeofsimulationcomplexity
• Mach1.6• EulerandReynolds-averagedNavier-Stokes(RANS)atflightunitReynoldsnumberof5.7millionpermeterrequested
• USStandardatmosphereat15,760meteraltitude
• Propulsionboundaryconditionsprovided
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C25F(shown)andC25P
5
DevelopedinAIAA-2016-2260andAIAA-2016-2261withEulermethod
• C25Fflow-throughnacelle(required)
• C25Ppoweredconfigurations(optional)
JWB• InversedesigntorecoverC25FequivalentareadistributionbyJAXAwithEulerandpanelmethods
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AXIE• InversedesigntorecoverC25Fnearfieldat3bodylengthsbyAndersonandAftosmiswithEulermethod
7
NearfieldEnsembleMeanR=3,PHI=0°
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9
C25PPressureDisturbance
dp/pinf
10
C25FPressureDisturbance
dp/pinf
11
JWBPressureDisturbance
dp/pinf
12
AXIEPressureDisturbance
dp/pinf
AXIE,C25F,andC25PProvidedGrids
• Mixedelementandtetrahedra onlyfamiliesofcoregridswithsemistructured Mach-alignedcollargrids(sameasSBPW1,seeAIAA-2014-115)– 0.6to56millionnodeEulerAXIE(5)– 3-104millionnodeEulerC25F(6)– 5-138millionnodeviscousC25F(6)– 3-52millionnodeEulerC25P(5)– 5-70millionnodeviscousC25P(5)
13
JWBProvidedGrids
• HeldenMesh generatedsurfaceandtetrahedralvolumegridswithanisotropicMach-alignedspacingfunctioninasinglegridtopology– 6,11,and18millionnodeEulerJWB(3)
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ParticipantGrids
• Participantsalsoprovidedgridsbasedontheirbestpractices– Gridsreceivedbeforetheworkshopwereavailableasoptionalgrids
• Aseriesofthreegridswasrequestedfromparticipantswithadaptivemethods– Finalgridandtwocoarserintermediates
15
• Subjectivemetrics• Thesehumanexperiencesarecorrelatedtonoisedescriptorsthroughexperiments– Leatherwoodetal.JASA2002– StevensMarkVIIPerceivedLevel(PL)
LoudnessandAnnoyance
16
ExpectedGridConvergence
• Consistentmethodsshouldapproachavalueasthegridisrefinedto“zero”h(inversecuberootofCFDcontrolvolumes,propagationfixed)
17CharacteristicGridLength(h)
Second-order
First-order
AXIEPLGridConvergence
AA AA
AA
AA
ABAB AB
AB
BA
BA
BA
BC
BC
BC
CA CACA
CA
CACC CC
CC
CC
CCDA DA
DA
DA
DA
DB DBDB
DB
DB
EA
EA
ECEC EC
FA FA FAGAGA GA GA GA GAHA HA HA
HA
IA IA IA
IA
IC
IC IC
JA JA
JAJC JD
KA
KA
KA
h
PL
(d
B)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
18
AA AA
AA
AAABAB
AB
AB
BA
BA
BA
BC
BC
BC
CA CACA
CA
CACCCC
CC
CC
CC
DA
DA DA
DA
DADB
DBDB
DB
DB
EA
EA EC
EC
EC
FA FAFA
GAGA GA GA GAGAHA HA HA
HAIA IA IA
IA
IC
IC IC
JA JAJA
JC JD
KA
KA
KA
hP
L (
dB
)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
R=3 R=5
• ParticipantDreportedthatthecollargridconstructionwasnotoptimalfortheirsolver
• ParticipantCreportediterativeconvergencedifficultiesinthecollargrid,butnotattheextractionlocation
EulerRANS
AXIEGridConvergence,R=5
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AA AA
AA
AAABAB
AB
AB
BA
BA
BA
BC
BC
BC
CA CACA
CA
CACCCC
CC
CC
CC
DA
DA DA
DA
DADB
DBDB
DB
DB
EA
EA EC
EC
EC
FA FAFA
GAGA GA GA GAGAHA HA HA
HAIA IA IA
IA
IC
IC IC
JA JAJA
JC JD
KA
KA
KA
hP
L (
dB
)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
• AnormofthesignatureistreatedlikethePLscalarandthesignatureispointwiseextrapolated(Richardson,Roache)fromthreegridstoinfinitelyrefinedgrid(h=0)
• Theredareaistheextrapolation,largestatshocks
EulerRANS
FA
AXIEGridConvergence,R=5
20
AA AA
AA
AAABAB
AB
AB
BA
BA
BA
BC
BC
BC
CA CACA
CA
CACCCC
CC
CC
CC
DA
DA DA
DA
DADB
DBDB
DB
DB
EA
EA EC
EC
EC
FA FAFA
GAGA GA GA GAGAHA HA HA
HAIA IA IA
IA
IC
IC IC
JA JAJA
JC JD
KA
KA
KA
hP
L (
dB
)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
• AnormofthesignatureistreatedlikethePLscalarandthesignatureispointwiseextrapolated(Richardson,Roache)fromthreegridstoinfinitelyrefinedgrid(h=0)
• Theredareaistheextrapolation,confirmingdivergence
EulerRANS
DA
JWBPLGridConvergence,PHI=10°
AB AB
AB
AE AE AEAE
BB
BB
BB
CCCC
CC
CC
CDCD CD CDDB DB DB
EA
EA EA
EB
EB EB
EC EC EC
FAFA
FA
GAGA GA GA GA GA
GDGD
GD
HB HB HBIA IA IA
JB JB JB
JC
JD
h
PL
(d
B)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
21
AB AB
AB
AE AE AE
AE
BB
BB
BB
CC
CC CC CC
CD CDCD
CD
DB DBDB
EA
EAEA
EB
EBEB
ECEC ECFA FA
FAGAGA GA GA GAGA
GDGD
GD
HBHB HB
IA IA IA
JBJB
JB
JC
JD
hP
L (
dB
)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
R=1 R=3
• JWBhasthestrongestexpansionandextractiondistancesensitivity
• JWBgridconstructiondifferentfromothermodels• JWBshowedthegreatestreconstructionlimitersensitivity
EulerRANS
C25FPLGridConvergence,PHI=0°
AC ACAC
AC
ACAC
AD AD
ADAD
AE
AE
AEAE
AFAF
AF
BB
BB
BB
CACA
CA
CACA
CA
CBCB
CB
CBCB
CB
CC CCCC
CCCC
CCCE CE
CE CE
CE
CF CFCF CF
CF
CG CGCG
CG CGCHCI
DADA DA
DA
DADA
DB DB
DB
DB
DB
EA EA
EBEB
ED EDED
FA
FA FA
GAGAGA GAGA
GAGBGBGBGBGBGB
GCGCGC
HCHC
HCHC
IAIA
IA
IB
JA JA
JAJCJD
KA
KAKA
KAKB
KB KBKC
KC
KDKD
h
PL
(d
B)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
22
ACAC AC
AC
AC AC
ADAD
AD AD
AE
AE
AE
AE
AFAF
AFBB
BBBB
CA CACA
CACA
CA
CB CBCB
CBCB
CB
CC CC CC
CCCC CC
CE CECE CE
CE
CF CFCF CF
CF
CG CG
CGCG CGCH
DADA DA
DA
DADA
DB DB
DB
DBDB
EA EA
EBEB
EDEDED
FA FA
FA
GAGAGA GA GAGAGBGBGBGBGBGB
GCGCGC
HC HCHC
HC
IAIA
IAIB
JAJA
JAJC JD
KA
KAKA
KAKB
KBKB
KC
KC
KDKD
hP
L (
dB
)
0 0.5 1 1.5 2 2.570
72
74
76
78
80
82
84
86
R=3 R=5
• Trendchangeforthefinermeshes(newphysics)• RANShasmorefinegridvariationthanEuler(smallergrids)• C25Phassimilartrends(whenupdatesaftertheworkshopincluded)
EulerRANS
StatisticalMethod
• Goalistoidentify“different”results,not“correct”or“wrong”
• Box(halfofsubmissions)andwhiskerplots(95%coveragefornormaldistribution)
• UsedbyDragPredictionWorkshop(AIAA-2017-1209)
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MedianMean
75%
25%
~5%
~95%
Outlier
PLEulerfromR=3
24
AXIE JWB C25F C25P
(deg) (deg) (deg) (deg)
C25FandC25PfromR=3
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C25FEuler C25PEuler
(deg) (deg) (deg) (deg)
C25FRANS C25PRANS
ProgressSinceSBPW1• MuchquietermeanPL(dB)– SBPW1:91.8axisymmetric,95.5wingbody– SBPW2:77.7axisymmetric,79.4wingbody
• Standarddeviationisdifficulttocompare,PL(dB)islogarithmic– SBPW1:0.3axisymmetric,0.2wingbody– SBPW2:0.6axisymmetric,1.4wingbody
• Morecomplexandmoresubmissions– Statisticsforrequiredfullconfiguration– Optionalpropulsionboundaryconditioncase
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Phi (degrees)
PL (d
B)
0 10 20 30 40 50 60848586878889909192939495
1A2B3C4C5C6C7E8M9O10Q11Q
Phi (degrees)
PL (d
B)
0 10 20 30 40 50 60848586878889909192939495
1A2B3C4C5C6C7E8M9O10Q11Q
27
LM1021PLCarpet,R=1.4
PHI(deg)
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C25FRANSPLCarpet,R=1
29
C25FEulerPLCarpet,R=1
Conclusions
• PLtrendswithgridrefinementwereshownfortheAXIE,JWB,andC25F– AXIEconvergencethebestwithoutliersatR=5– AXIEobservationsatR=5confirmedwithexaminationofnearfieldsignatureconvergence
– JWBhadalargervariationthanthemorecomplexC25F
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Conclusions
• PLstatisticsvisualizedwithboxandwhiskerplots– EulerandRANSanalyzedseparatelywhensufficientsamplesavailable
– Thesizeofthebox(middle50%)waslargestfortheJWBEuler
– RANShaslargerboxthanEulerforC25FandC25P
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Conclusions
• Progressmadesincethefirstworkshopidentified– Simplecasesmuchquieter– JWBhadalargerstandarddeviation,butPLlogrithmic
– StatisticsavailableforcomplexC25FandC25P
32
InthePaper
• Gridconvergenceofnearfieldsubmissions– ConfirmsandexplainsthetrendsshowninPL
• Pointwisemeanandstandarddeviationofnearfieldsubmissions– EulerandRANSnearfielddifferbymorethanonestandarddeviationinmanyimportantlocations
• Liftanditerativeconvergence– EulerandRANSliftapproachdifferentvalueswithgridconvergence
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InthePaper
• Detailsofrequiredgridfamilies• Summariesofparticipantpresentations• Discussion,recommendations,andnextstepstowardSBPW3– QuieterSBPW2casesexposedissuesnotseeninSBPW1
– Quieterconfigurations,ideallyatorbelow75PL(dB)– Additionalresearchneededtoreducesensitivitytoconvectionscheme
– Establishingbenchmark(archivedsubmissions)
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Acknowledgments• Allparticipants• MathiasWintzer,IrianOdaz,JamesFenbert,andSriram Rallabhandi
forC25FandC25Pdesigns• GeorgeAndersonandMichaelAftosmis forAXIEdesign• AtsushiUeno,MasashiKanamori,andYoshikazuMakinoforJWB
geometry• AndrewClemensforJWBgrids• MarieDenisen,Adrein Loseille,Alaa Elmiligui,andMikeAftosmis
forgridevaluationandfeedback• ScottBrynildsen,BillJones,andSriram Rallabhandi forgeometry
preparation• JoeDerlaga forstatisticaltools• NASACommercialSupersonicTechnologyProjectofthe
FundamentalAerodynamicsProgram.
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PerceivedLevel(PL)
• Signaturesoundpressurelevelisgatheredinto1/3octavebands
• Bandlevelsareconvertedintosones(loudness)
• Sones fromeachbandarecombined
• Sones areconvertedintoPLvialogarithm
Nearfield Plotting
• Tauisdistancefromfreestream Machconeoriginatingattipofnose
• Deltapressuredividedbyfreestream pressureisscaledbythesquarerootofradius inbodylengths– Signaturesatdifferentradiireadilycomparableand“aging”effectobserved
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R