1、Copy 205RM L52K06,. -PRESSUREDISTRIBUTIONJD P% SSUREDRAGFORA HEMISPHERICALNOSEAT MACH.NUMBERS2.05, 2.54, AND 3.04. /.By Leo T. ChauvinLangleyAeronauticalLaboratoryLangleyField, Va. .CMSIFIEDmubmmfensgofb miltedSlataaWlthlnttnIu13ai!hfNATIONALADVISORY COMMITTEEFOR AERONAUTICSWASHINGTON12ecember31, 19
2、52Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1s9.NACAFML52K06 NATIONALADVISORYCOMMITTEEFORRESEARCHMEMORANDUMPRESSUREDISTRIBUTIONANDPRESSUREDRAGFURA HEMISPHERICALNOSEATMACHNUMBERS2.05,2.54,AND3.04ByLeoT.ChauvinsuMMARYrAnexperimentalinvestigationo
3、fthepressuredistributionsonahemisphericalnose3.98 inchesindiameter,mmntedona cylindricalsupport,hasbeenmadeatMa nbersof2.05,2.54,and3.04 andforReynoldsnumbersof4.44 x 106,k.57 x 106,and4.16 x 106,respectively.TheReynoldsnumberwasbasedonbodydiameterandfree-streamconditions.Pressure-dragcoefficientswe
4、recalculatedandgoodagreementwasobtainedbetweenthesetestssndotherinvestigations.INTRODUCTIONFromthestandpointofminimumdrag,highfineness”ratiosandnearlypointednosesaredesirableinthedesignofsupersonicmissilesandair-planes.However,itisnecessaryforsomesupersonicvehiclestohave“ahemisphericalnosetohousegui
5、danceequipment.Sinceuseofthisnoseshapemayresultinseveredragpenalties,-withcorrespondingreductioninspeedandrange,theNationalAdvisoryCommitteeforAeronauticshasmadetestsinthepreflightjetandinfreeflighttodeterminethepres-suredrag,pressuredistribution,andaerodynamicheatingofhemispher-icalnosebodies.Thete
6、stsweremadeattheIangleyPilotlessAircraftResearchStationatWallopsIsland,Va. Flighttests.todeterminethedragofseveralround-nosedbodiesatsupersonicspeedshavebeenreportedinreference1. Thepresentpaperpresentsthedataobtainedfrompres-suremeasurementsatMachnumbersof2.05,2.54,and3.04andforReynoldsnumbersof 4.
7、44 x 106,4.57 x 106,and4.16 x 3.06,respectively.TheReynoldsnumberwasbasedonbodydiameterandfree-streamcondition.I1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MCPPP()V.%P.Rxrw 7%$.:, j: .:-, -SYMBOISMachnumberP -PO pressurecoefficient,. QNACAM L52K
8、06-bpv200body,lb/sqin.abs .-pressure,lb/sqin.absstaticpressureonfree-streamstaticfree-streamvelocity,ft/sec pressure-dragcoefficier+tstagnationpresse,lb/sqin.absfree-streamdensity,slugs/cuf% . .Reynoldsnumber,basedonbodydianetercoordinateinfree-streamdirectionradiusofhemispherical.nose .- TEST EQUIP
9、MENT Thetestsweremadeinthe8-inchauxiliaryJetoftheweflitjetoftheLangleyPilotlessAircraftResearchStationatWailops-Island,Va. Airfortheoperationoftheprefldghtjetwasstoredintwospheresat220poundspersquareinchabsolute.A hdraul.icallycontrolledvalveregulatedthe airfromthesphere.The_airthenpassedthroughahea
10、texchatigerwhereitwasheatedsufficientlytocompensate fortheadiabatictemperaturedropthroughthesupersonicnozzle.Theairnextpassedthroughathree-dimensionalnozzleandexhaustedtotheatmosphere.DifferenttestMachnumberswereprovidedbyinterchange-ablenozzles.A shadowaphsystemwasprovidedforflowobservations.Furthe
11、rinformationconcerningthepreflightjetcanbefoundin u“reference2.a71Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACARML52K06 -Themodelwasahemisphericalnose3.983inchesindismeter,mountedona cytidricalsupport,alinedwiththecenterlineoftheje.Four-teenpr
12、essureorificeswerelocatedonthenoseandspiraledrearwsrdofthestagnationpetitto0.6inchonthecylindricalportionofthebody.TheratioofmodeldismetertoJetdismeterwas0.498forthe M = 2.05andM= 2.54 testsand0.532forthe M = 3.04test.Figure1 showsthegeneralarrangementofthenosemountedinthe8-inchauxiliaryjet.Thetestn
13、osewasmadefromspunK-Monel0.05inchthick,withasmoothandhighlypolishedsurface.Measurementsofthefree-stresmtotalpressure,free-streamstagna-tiontemperature,andpressuresonthebodywereo%tainedbya sti-cellrecordingmsmmeter,thermocouples,andelectricalpressurepickups,respectively.Thesedatawererecordedbyusingtw
14、orecordinggalva- nometerssndoneopticalrecorder.Thethreerecordersweresynchronizedwitha tdmerof10cyclespersecond.Theinstrumentsusedwereaccurateto1percentoftheirfullscale.Theorificesonthemodeldatapresentedweretakentiensteadycondition.were0.04-imhinsidedismeter,andthethepressuresonthebodyhadreachedaTEST
15、CONDITIONS4.44TheReyuoldsnumbersfortheMachnunibers2.05,2.54,smd3.04werex 106, 4.57 x 106, ad 4.16x 106, respectively.TherelativelyconstantReynoldsnwnberofthetests&s duetothevariationofstaticpressureandtcanperature.Thetestat M = 2.05wasfora sea-levelcondition.Theconditionsforthetestsat M =2.54 and M=
16、 3.04representeda staticpressurecorrespondingtoaltitudesof12,000and28,000feet,respective.RESU22TSThetestresultsforMachnumibers2.05,2.54,snd3.04areshowninfigure2plottedaspressurecoefficientasa functionofthenondtien-sionalparsmeterxr,wherex isthedistanceW thestreamdirectionfromthestagnationpetiton,the
17、nosetothemeasurementstationand ristheradiusofthehemisphere.Figure2(a)showstheresultsfortwotestsmadeat M =2.05 andatapproximatelythessmefree-streamtotalpressure.Thisfigureshowsthatthepressuremeasumnentscanberepeatedtitigoodaccuracyandthatnoduplicationofthetestsisneeded.Provided by IHSNot for ResaleNo
18、 reproduction or networking permitted without license from IHS-,-,-4 NACARML52K06Figure3 showsa shadowgramtakenforeachtest.Shockseminating 9fromtheedgeofthenozzleintersectthebowwaveand7influencetheflowsomewhereonthebody.Iftheintersectionwasbetweenthestagna-tionpointofthebodyandthesonicpointofthebody
19、,thepressure *overtheentirenosewouldbeaffected.ForeachMachnumbertestedthesonicpointwasestimated,and,ineachcase,thenozzleshockwasfoundtoliewelloutsidethemibsonicregion.Forthe M =2.0 andM= 2.54 tests,thedisturbancefromtheintersectiondoesnotaffecttheflowoverthehemisphere.Forthe M = 3.04 case,however,th
20、edisturbmcefromintersectionwasstrongerandcauseda standingshocktooccuronthehemisphereatavalueof xjr ofapproximately0.71(seefig.3(c).Rearwardofthispetitthe.measuredpressureswereaffectedbythisdisturbancead nodatawerepresentedforavalueofx/r greaterthan0.66.dragfor M = 3.04,thefigure3(c).Figure4 showsthe
21、coefficientsplottedasForthepurposeofcalculatingthepressuredatawereextrapolatedto,$ =.1.0,asshownhfairedcurvesthroughthepointsofpressureafunctionof x/r for M =2.05 ofthisseriesoftests.Alsoshownaretherestsfromreferences3 and4takenat M =1.90 and M = 1.62amdatReynoldsnmnbersofapproxi-matelyO. x 106and0.
22、811x 106,respectively.Thedatafromrefer-ence3 wereobtainedwithahaisphericalnoseattachedtoa cylindricalbody,andthedataframreference4werecalculatedfrominterfercuneterobservationsona sting-swpportedsphere. Thepressure-dragcoefficient,plottedasa functionofMachnunber(fig.5), wascalculatedbyintegratingthep
23、ressuresromthepresenttestsandfromreferences3 and4. Pressure-dragcoefficientsobtatiedfromreference5areshowninfigure5 forMachnumbersof1.5, 1.98,and3.02.Thedatafromthereferences3to5correlatewellwiththefairedcurvethroughthepointsCalculatedf%mCONCLUDINGREMARKSthesetests.Pressuredistributionsweremeasuredo
24、nahemisphericalnose3.98inchesindismeteratMachnumbersof2.05,2.54,and3.04andfor”Remoldsnumbersof4.44x 106,4.57x 106,and4.I-6x 106,respectively.TheReynoldsnuuiberforthesetestswas based onbodydismeterandfree-streamconditions.Thepressure-dragcoefficientsobtainedfromprevious.9.- - - .Provided by IHSNot fo
25、r ResaleNo reproduction or networking permitted without license from IHS-,-,-*NA$!ARML52K06 5investigationsareinagreementwiths,fairedcurvethroue pointsofpressure-dragcoefficientcalculatedfromthesetests.LangleyAeronauticalLaboratory,NationalAdvisoryCommitteeforAeronautics,LsngleyField,Va.REFERENCES1.
26、Hart,RogerG.: FlightInvestigationoftheDragofRound-NosedBodiesofRevolutionatMachNumbersFrom0.6to1.5UsingRocket-PropelledTestVehicles.NACARML51JZ25,1951.b.2.Faget,MaxtieA.,Watson,RaymondS.,dBartlettWalterAs)Jr.:Free-JetTestsofa 6.5-Inch-DismeterRem-JetEngineatMachNunbersof1.81end2.00.NACARML50L06,1951
27、.3.Moeckel,W.E.: ExperimentalInvestigationofSupersonicFlowWithDetachedShockWavesforMachNuribersBetween1.8and2.9.NACARME50D05,1950.4. Wood,GeorgeP.,andGooderum,pati.: MethodofDetermfigInitialTangentsofContoursofFlowVariablesBehindaCurved,Axial.lySymmetricalShockWave.NACATN241-1.j1951.5. Somner,SimonC
28、.,andStark,JamesA.: TheEffectofBluntnessontheDragofSpherical-TippedTruncatedConesofFinenessRatio3atMachNumbers1.2to7.4.NACARMAZB13,1952.“-.rProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-i.”i”:, Ww”i “” “Ilh.-.Figure 1.- Photogaph of model mounted i
29、n the 8-inch auxiliery jti.L-785. .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. . a71+. H(j-115.7.4painU Ho=116.05paiaI I R=4.4AXIJ36o a712 d .6 .8 1.0 1.2 1.4&F(a) M = 2.05.Figure2.- Pressure distribution on a hemispherical nose.iia71 ll.-JProv
30、ided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2.011“7Q 1.2)CJ.8.40-.4&.,0 .2 .4(b)Figure.6 .8xrM = 2.34.2.-Continued.d- =169.8PSiaR=4.57x N#T+1.0 1.4a7103. . . .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from I
31、HS-,-,-,2.01.6“m 1.2i .80ii 40-.4Ho=185.7p6iaR.4.16xlo6FI I.8 1.0 1,2 1xr(c) M = 3.04.Figure2.- Concluded. aProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-(a) M=2.oIj.Figure 3ShadowgraUIforeachtest.,L-7k787.IProvided by IHSNot for ResaleNo reproduct
32、ion or networking permitted without license from IHS-,-,-. .*(b) M = 2.74.Figure3.-Conttiued. L-74788 .1 b!-J.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-II!l(c)FigureM =3.04.3.-Concluded. L-74789.2.-, IProvided by IHSNot for ResaleNo reproductio
33、n or networking permitted without license from IHS-,-,-“*M2.05 Premat beet l. Refermce3 1.62 Refemmce4o .2 4 .6 .8 1.0 1.2 l&xFFigure4.-Pressure dlstri,butionon a hemisphere for M . E.O5 testand references 3 and 4.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-PL-1.2.8.4- Present teats+ Reference 3 Refermce h+% Referencel.O 1.4Figure 5Variation of1.8 2*2 2.6 3.0Maahnumber, Mpressure-drag coefficient with Mach numberforahemisphere.3*4. .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
