Flight, Wind-Tunnel, and Computational Fluid Dynamics Comparison for Cranked Arrow Wing

168 Pages·2001·7.19 MB·English

NASA/TP-2001-210629
Flight, Wind-Tunnel, and Computational
Fluid Dynamics Comparison for Cranked
Arrow Wing (F-16XL-1) at Subsonic and
Transonic Speeds
John E. Lamar, Clifford J. Obara, and Bruce D. Fisher
Langley Research Center, Hampton, Virginia
David F. Fisher
Dryden Flight Research Center, Edwards, California
February 2001
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NASA/TP-2001-210629
Flight, Wind-Tunnel, and Computational
Fluid Dynamics Comparison for Cranked
Arrow Wing (F-16XL-1) at Subsonic and
Transonic Speeds
John E. Lamar, Clifford J. Obara, and Bruce D. Fisher
Langley Research Center, Hampton, Virginia
David F. Fisher
Dryden Flight Research Center, Edwards, California
National Aeronautics and
Space Administration
Langley Research Center
Hampton, Virginia 23681-2199
February 2001
Acknowledgments
Many individuals contributed to the gathering of the flight, wind-tunnel, and computational data in this report. A
highlyintegratedeffortwasrequiredinordertocomparethesedata.Tothatend,aby-productofthispaperwasthe
developmentofahighlyskilledandmotivatedteam. Thisteamconsistedprimarilyofdirectmanagementandsoftware
supportfromtheLangleyResearchCenter(LaRC)andtheComputerSciencesCorporation(CSC),SystemsSciences
Division, Hampton, VA. At LaRC, the key people were Kathryn Stacy, Kurt S. Severance, Catherine K. Cronin,
DonaldP.Randall,PatriciaA.Kerr,MichaelD.Weisenborn,SusanJ.Rickard,andDavidE.Hahne;atCSC,thekey
people were Christine G. Matthews, Dana P. Hammond, Raymond L. Gates, Robert C. Auberg, Joseph F. Reisel,
Gerald H. Mall, Susan S. Bowen, S. Blake Williams, Rachel Gartenberg, Norma F. Bean, Javier A. Garriz, and
DavidA. Wolverton. Individual contributions ranged from data translation done by Patricia A. Kerr, Dana P.
Hammond,andRobertC.Auberg;imagefusionsdonebyKathrynStacy;specialdatacomparisonsdonebyKurtS.
Severance, David A. Wolverton, GeraldH. Mall, Susan S. Bowen, S. Blake Williams, Rachel Gartenberg, and
StephenJ.Alter,LockheedMartinEngineeringandSciencesCorporation,Hampton,VA;databasemanagementwork
donebyCatherineK.Cronin,DonaldP.Randall,JosephF.Reisel,andRaymondL.Gates;initialgeometry,compu-
tational gridding, and solution work done by Anutosh Moitra, High Technology Corporation, Hampton, VA; final
geometryandcomputationalgriddingworkdonebyNormaF.Bean;initialcomputationalsolutionsonfinalgridper-
formedbyJavierA.Garriz;computationalcameralocationandviewingworkdonebyMichaelD.Weisenborn;and
low-speed wind-tunnel data provided bySusanJ.Rickard and David E. Hahne.
TheauthorswishtothankthefollowingpeoplefromLaRCforthemanyhelpfulsuggestionsarisingfromtheirreview
ofthismanuscript:LaurenceD.Leavitt,JerryM.Allen,ScottG.Anders,JayM.Brandon,WendyB.Lessard,KurtS.
Severance,andGeorginaR.BrancoofNASADrydenFlightResearchCenter.Also,thanksaregiventotheLibrary
and Media Services Branch of the Langley Research Center who published this document, with special
acknowledgmenttotheNCITechnicalPublicationsSupportGroupatLangley(LeannaDeeBullock,EloiseJohnson,
Una Thomas, Martha Jones, Patricia Gottschall, Mary Edwards, and Cathy Everett).
The use of trademarks or names of manufacturers in this report is for accurate reporting and does not constitute an
officialendorsement,eitherexpressedorimplied,ofsuchproductsormanufacturersbytheNationalAeronauticsand
Space Administration.
Available from:
NASA Center for AeroSpace Information (CASI) National Technical Information Service (NTIS)
7121 Standard Drive 5285 Port Royal Road
Hanover, MD 21076-1320 Springfield, VA 22161-2171
[phone] [phone]
Contents
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Flight, CFD, and Wind-Tunnel Surface Pressures . . . . . . . . . . . . . . . . . . . . . . 1
Boundary Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Data Fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Basic Data Typesand Test Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Airplane description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Detailsand comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Data collected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Procedures and accuracy of data collection . . . . . . . . . . . . . . . . . . . . . . 3
Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Visual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Hot(cid:12)lm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
WindTunnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
0.11-scaled model tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
0.18-scaled model test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
0.04-scaled model test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
CFD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
CFL3D (cid:13)ow solver code and grid . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Computer requirements andsample convergence histories . . . . . . . . . . . . . . . . 6
Using the solution (cid:12)le . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
CFD Comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Surface Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Subsonic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Transonic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Boundary-Layer Pro(cid:12)les at FC7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
SkinFriction at FC 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Onand O(cid:11) Surface Flow Features at FC 46 . . . . . . . . . . . . . . . . . . . . . . . . 11
EFD Basic Data andComparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Forcesand Moment in WindTunnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Surface Pressures in Wind Tunnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
E(cid:11)ect of model scale and Rn on Cp atlow speed . . . . . . . . . . . . . . . . . . . . 11
Transonic C contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
p;u
iii
Onand O(cid:11) Surface Flow (Air Dams O(cid:11))in Wind Tunnel . . . . . . . . . . . . . . . . . . 12
Surface Flow in Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Appendix A|Visualization Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Appendix B|Data Processesand Management . . . . . . . . . . . . . . . . . . . . . . . 17
Appendix C|Airplane Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Appendix D|Description ofWind-Tunnel Test and Vapor-Screen Systems . . . . . . . . . . . 29
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
iv
Symbols
A wing aspect ratio, b2 , 1.75
S
ref
AMRAAM advancedmedium range air-to-airmissile
BART Langley Basic Aerodynamic Research Tunnel
BL butt line onairplane, positive on right wing, in. (see (cid:12)g. 2)
b wingspan, 32.4 ft(full scale)
CD drag coe(cid:14)cient
C lift coe(cid:14)cient
L
Cm pitching-momentcoe(cid:14)cient
Cp static-pressure coe(cid:14)cient
CAWAP Cranked-Arrow Wing Aerodynamics Project
CFD computational (cid:13)uiddynamics
c local skin friction coe(cid:14)cient
f
cr theoretical root chord for F-16XLairplane, 41.75 ft(full scale)
(cid:22)c reference wing chord, 24.7 ft(full scale)
EFD experimental (cid:13)uid dynamics, (cid:13)ight- or ground-based measurements
ESP electronic scanning pressure
FAST Flow Analysis Software Toolkit
FC (cid:13)ight condition
Flt (cid:13)ight number
FS fuselagestation on airplane, positive aft, in. (see (cid:12)g. 2)
FV (cid:13)ow visualization
GPS global positioning system
HF hot-(cid:12)lm sensors
HUD heads-updisplay
h altitude, ft
I.D. inside diameter
i;j;k grid indices
L2 (residual) residual of the L2 norm plotted on log scale
LE leading edge
LS, low lowersurface
LT loadedturn
M Mach number
M1 free-stream Mach number
NAS Numerical Aerodynamics Simulation
O.D. outside diameter
PGME propylene glycol methyl ether
v
PrISM Program forInformation Storage andManagement
PSP pressure sensitive paint
PT modi(cid:12)ed Preston tubes
p free-stream static pressure, lb/ft2
q1 free-stream dynamic pressure, lb/ft2
Rn Reynolds number, (cid:13)ight value computed by 1:2583(cid:22)cpM1 (cid:16)T +T1298:72(cid:17)106 (basedon
ref. 1, eq. I.3.8-(1)); in (cid:12)gure keys, R is used for Reynolds number
0:5
R Reynolds number based on momentum thicknessascomputed by (cid:25)0:407sin(70) Rn=ft
(cid:18) hcos (70)i
RK boundary-layer rake
r radius
S reference wing area, 600 ft2 (full scale)
ref
SLFC supersonic laminar (cid:13)ow control
(cid:14)
T absolute temperature, R
TE trailing edge
US,up uppersurface
V=V ratio of velocity magnitude inboundary layer to thatat rake extreme total-pressure
RE
tube
VCR video cassette recorder
WL waterline on airplane, positive up, in. (see (cid:12)g. 2)
WT windtunnel
WUT wind-up turn
WWW World Wide Web
x=c fractional distance along local chord, positive aft
y normal distance above surface at rake location, in.
y+ Reynolds number like term for (cid:13)at-plate turbulentboundary layer(ref. 2)
(cid:11) angle of attack, deg
(cid:12) angle of sideslip, deg
(cid:20);(cid:30);! Euler angles for camera orientation, deg (see (cid:12)g. C6)
2y=b fractional distance along local semispan, positive on rightwing
2-D two-dimensional
30 by 60 Langley 30- by 60-Foot Tunnel
3-D three-dimensional
Subscripts:
avg average value
nom nominal value
u uppersurface
vi
Summary than2 at(cid:13)ightconditions; infact, they were (cid:25)82.
The\wallfunction"optioninthecodeprovedsu(cid:14)-
This report summarizes an e(cid:11)ort to compare
cientatsubsonic speedstorepresentthe boundary
geometrical, (cid:13)ight, computational (cid:13)uid dynamics
layers underneath attached (cid:13)ow and the primary
(CFD), and various wind-tunnel studies for the
vortex but insu(cid:14)cient underneath the secondary
F-16XL-1 airplane and uses data fusion (overlay-
vortex system at nominal angle of attack of 13(cid:14).
ing)whereverpossibletoprovideadditionalinsight
Moreover, the (cid:13)ight data indicate the presence of
into the data sets. The resulting highly diverse
an interaction of the secondary vortex system and
types ofdata sets were obtainedover a wide range
boundary layer, and the boundary-layer measure-
of (cid:13)ow test conditions and have produced some
mentsshowthatthe secondary vortex was located
novel results.
more outboard than predicted. Qualitative agree-
Geometry
ment exists between predicted and measured skin
With respectto geometry, the upper surface of
friction spanwise distributions because both CFD
the airplane and the numerical surface description
and (cid:13)ight results show at least tworegionsof high
have a reasonably good comparison. The largest
local skin friction coe(cid:14)cient (cf), indicative ofpri-
di(cid:11)erence measured over the wing was 0.24 in.
mary and secondary vortex presence, andthey oc-
cur at spanwise positions near one another. How-
Flight, CFD, and Wind-Tunnel Surface
Pressures ever, the absolute levels of cf and the indicated
spanwise extent ofthe vortices di(cid:11)er.
For (cid:13)ight and CFD pressures, overall compar-
isonshave beenexpedited by use of computational Data Fusion
graphical tools. At subsonic speeds, reasonably
Data fusion (overlaying) has been applied to a
goodagreementwasnotedatanglesofattackupto
10.4(cid:14). Forangles of attack above 10.4(cid:14), the agree- variety of (cid:13)ow-visualization techniques for (cid:13)ight,
wind-tunnel, and CFD investigationswithinsight-
mentswere muchpoorerbecause the suctionpeaks
were underpredicted. At transonic speeds, gener- ful results. Among these are (1) combined surface
ally good pressure agreementwas noted, especially tufts images from three (cid:13)ight cameras compared
withCFD surface streamlines and vortex-core rep-
near the inboard leading edge at angle of attack
((cid:11)) of 4.4(cid:14) and free-stream Mach number (M1) resentationatM1 =0:53and(cid:11)= 10.4(cid:14) showgen-
erally good comparison; (2)the (cid:13)ightresults ofoil
of 0.97. The e(cid:11)ect of small trailing-edge control-
surface de(cid:13)ections ((cid:20)2(cid:14)) in (cid:13)ight, not modeled in (cid:13)ow with tufts and liquid crystals with tufts com-
CFD, led to pooreragreementforthe aft pressures pared well; and (3) the wind-tunnel comparison
of vortex-core and reattachment-point locations|
and a shock not predicted. By contrast, an ex-
perimental (cid:13)uid dynamics comparison ofthe pres- as determined from vapor screen and
sure contours from the wind tunnel at(cid:11) =4(cid:14) and compared with surface oil-(cid:13)ow traces|though
M1 =0:95withtheaforementioned(cid:13)ightdatadid showing promise, point to the need for further re-
show a wind-tunnel shock location near the hinge (cid:12)nement.
line fortheaileron,whichgenerallyisinqualitative
Introduction
agreementwiththatdeterminedfromthetransonic
(cid:13)ightresults. The increasing capability of CFD to simulate
real airplane geometries and (cid:13)ow conditions is
Boundary Layer
found in the literature for both (cid:12)ghter and trans-
Anticipated relaminarization of the boundary portairplanes,forexample,theF-18HARV(ref.3)
layerunderthein(cid:13)uence ofhighsuctionpeaksnear andthe MD-11 (ref. 4). In the continuance of that
the leading edge was not supported by the tur- trend, thisreport details the resultsof a compara-
bulent signal output from (cid:13)ight hot-(cid:12)lm gauges. tive study ofCFD,(cid:13)ight, andwind-tunnel datafor
Thus, the (cid:13)ight leading-edge attachment line was the F-16XL-1airplane ((cid:12)g. 1)over a wide range of
turbulent;thisputsthisdatasetinagreementwith test conditions from subsonic to transonic speeds.
other(cid:13)ightdata. ThegridusedintheCFL3Dcode Thoughthisairplane is not new, its cranked-arrow
produced Reynolds number like term for (cid:13)at-plate planformisrelevanttoanyhigh-speed(supersonic)
turbulent boundary layer (y+) values much larger (cid:12)ghter or transport, for example, the High-Speed
Civil Transport. When the F-16XL-1 airplane given type, for example, wind tunnel only. (Ref. 7
was new, the kinds of testing done were related detailswhatwaslearnedaboutthe boundary-layer
to its operational characteristics (refs. 5 and 6) (cid:13)ow over the F-16XL-2 airplane|the one used in
and not focused on an understanding of its ba- the supersonic laminar (cid:13)ow control (SLFC) (cid:13)ight
sic (cid:13)ow physics, the subject of the current inves- experiments.)
tigation. This understanding was the subject of
In addition to the basic comparison e(cid:11)ort, a
the Cranked-Arrow Wing Aerodynamics Project
brief introduction on the use of associated visual-
(CAWAP) and the results reported herein. Since
ization software tools is given in appendix A, and
CFD predictions are being sought for purposes of
a descriptionofthe data processesandmangement
comparison with measured data for this airplane,
system used for this project is given in appen-
knowledge of the airplane geometry is (cid:12)rst neces-
dix B. Appendixes C and D contain a description
sary. Hence, a geometrical comparison was under-
of the airplane instrumentation usedand the asso-
takenforthecomplete airplane, includingwingtip-
ciated wind-tunnel testand vapor-screen systems,
mounted missiles and tail. Other comparisons are
respectively.
made between (cid:13)ight, wind-tunnel, and CFD data.
The scope of the planned comparisons was ex- Basic Data Types and Test Conditions
tensive, as shown in table 1; however, not all the
Four basic data types are associated with this
neededdata were collectedduring the testing pro-
comparison e(cid:11)ort. Each type is important in its
cess or proved reliable with the latter essentially
own right and when utilized together form the
eliminating the load-factor and Rn (cid:13)ight studies.
basis for this comprehensive undertaking. The
Along with other constraints, this has led to the
data types are geometry, (cid:13)ight, wind tunnel, and
availability of only a subset of comparisons as de-
CFD.
tailed in table 2. The reasons for the dearth of
datacollectionrange from pressure sensitive paint
Geometry
(PSP) not yet calibrated for use in (cid:13)ight, along
withotherimagingandprocessingissues; hardware Airplane description. The F-16XL-1 is a
forthe (cid:13)ightvapor screen notavailable during the single-place (cid:12)ghter-type prototype airplane de-
testing time; and resource constraints forced the veloped by the General Dynamics Corporation,
elimination of the propylene-glycol-methyl-ether Ft. Worth Division (now the Lockheed Martin-
(PGME) trace (cid:13)ight experiment. In addition to Tactical Aircraft Systems) by stretching the fuse-
these, at least two other planned tasks were also lage of a full-scale development F-16A and adding
notfully accomplished. Forexample, (1)the mod- a cranked-arrow wing, a modi(cid:12)edfuel system, and
i(cid:12)ed Preston tubes used to determine local skin a modi(cid:12)ed(cid:13)ightcontrol system. Thisairplanehad
friction were to be located at the same fuselage scheduled leading-edge (cid:13)aps, elevons, andailerons
station as the boundary-layer rakes, but a more on the wing for control. The technical speci(cid:12)ca-
aftpositionforthe tubes was necessitated because tions for the airplane are given in table 3. Details
of easier installation on the airplane and avoiding onthe constructionofthe airplaneanditsintended
the (cid:13)ow o(cid:11) a step in the leading-edge region and missions are given inreferences 5, 6, and8.
(2) an attempt to correct the transition point lo-
The design of the cranked-arrow wing was a
cationusedinCFD fromthe leadingedge tosome
cooperative e(cid:11)ort of the Langley Research Cen-
point aft proved unnecessary at (cid:13)ight conditions
ter and the General Dynamics Corporation. The
because theleading edgewasalready turbulentac-
newwingwasdesignedtoprovidethe F-16airplane
cording to hot-(cid:12)lm measurements.
withimprovedsupersonic performancewhile main-
Notwithstandingtheseissues, anumberofcom- taining transonic performance comparable with
parisons were made; these include on and o(cid:11) sur- that provided by the current F-16 design. As
face (cid:13)owcharacteristics, thatis, surface pressures, shown in (cid:12)gure 2, the resultant design had a
(cid:14) (cid:14)
upper surface (cid:13)ow, boundary-layer velocity pro- leading-edge sweep angle of 70 inboard and 50
(cid:12)les, and local skinfrictiondistribution, aswell as outboardofthe crank. Atthe juncture ofthe wing
force and moment where possible. These compar- leading edge withthe fuselage, an\S-blend curve"
isonsare followedby analyses ofdatasetswithin a was placedin the leading edge to alleviate a pitch
2