NUMERICAL INVESTIGATION OF FLOW CONTROL OVER AN

90 Pages·2008·15.92 MB·English

NUMERICALINVESTIGATIONOFFLOWCONTROL
OVERANAIRFOILWITHSYNTHETICJETSANDITSOPTIMIZATION
ATHESISSUBMITTEDTO
THEGRADUATESCHOOLOFNATURALANDAPPLIEDSCIENCES
OF
MIDDLEEASTTECHNICALUNIVERSITY
BY
ERAYAKC¸AYO¨Z
INPARTIALFULFILLMENTOFTHEREQUIREMENTS
FOR
THEDEGREEOFMASTEROFSCIENCE
IN
AEROSPACEENGINEERING
SEPTEMBER2008
Approvalofthethesis:
NUMERICALINVESTIGATIONOFFLOWCONTROL
OVERANAIRFOILWITHSYNTHETICJETSANDITSOPTIMIZATION
submitted by ERAYAKC¸AYO¨Z inpartialfulfillmentoftherequirements forthedegreeof
Master of Science in Aerospace Engineering Department, Middle East Technical Uni-
versity by,
Prof. Dr. CananO¨zgen
Dean,GraduteSchoolofNaturalandAppliedSciences
Prof. Dr. ˙IsmailH.Tuncer
HeadofDepartment, AerospaceEngineering
Prof. Dr. ˙IsmailH.Tuncer
Supervisor, AerospaceEngineeringDept.,METU
ExaminingCommitteeMembers:
Prof. Dr. CahitC¸ıray
Aerospace Engineering Dept.,METU
Prof. Dr. ˙IsmailH.Tuncer
Aerospace Engineering Dept.,METU
Prof. Dr. M.HalukAksel
Mechanical Engineering Dept.,METU
Assist. Prof. Dr. Og˘uzUzol
Aerospace Engineering Dept.,METU
Dr. SartukKarasoy
Manager, ROKETSANA.S¸.
Date:
Iherebydeclare thatallinformation inthisdocumenthasbeenobtainedandpresented
in accordance with academic rules and ethical conduct. Ialso declare that, as required
bytheserulesandconduct,Ihavefullycitedandreferencedallmaterialandresultsthat
arenotoriginaltothiswork.
Name,LastName: ErayAkc¸ayo¨z
Signature :
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ABSTRACT
NUMERICALINVESTIGATIONOFFLOWCONTROL
OVERANAIRFOILWITHSYNTHETICJETSANDITSOPTIMIZATION
Akc¸ayo¨z, Eray
M.S.,DepartmentofAerospaceEngineering
Supervisor : Prof. Dr. ˙IsmailH.Tuncer
September2008,73pages
Inthiswork,anactiveflowcontrolmethodisstudiednumericallybyusingasyntheticjetover
a NACA 0015 airfoil. Unsteady, turbulent flows over the NACA 0015 airfoil are computed
usingaNavier-Stokessolver. TheSpalart-Allmarasturbulencemodelisemployedinallcom-
putations. Unsteady flow solutions are computed in parallel using Parallel Virtual Machine
libraryroutinesinacomputercluster. Thesyntheticjetisimplementedtotheflowsolverasa
boundarycondition. ResponseSurfaceMethodologyisemployedfortheoptimizationofsyn-
theticjetparametersatvariousanglesofattack. Thesyntheticjetparameters;thejetvelocity,
thejet location, thejetangle andthejet frequency areoptimized tomaximize thelift todrag
ratio. The optimization study is performed for aconstant value of jet power coefficient. The
jetslotsizeisusedasadependent parameterintheoptimization studies.
The optimization study has shown that the jet velocity and the jet location are the dominant
synthetic jet parameters. The optimum synthetic jet angle is observed to be increasing as
the angle of attack increases. The optimum jet location is observed to be moving through
the leading edge as angle of attack increases for the separated flows. It is observed that the
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application of the synthetic jet delays the flow separation on the suction side of the airfoil
and increases the lift to drag ratio significantly especially at post stall angles of attack. The
application ofthesynthetic jetisobserved tobelesseffectiveforattachedflows.
Keywords: FlowControl,SyntheticJets,Optimization,ParallelProcessing,ResponseSurface
Methodology
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O¨ Z
KANATKES˙ID˙IU¨ZER˙INEYERLES¸T˙IR˙ILEN
SENTET˙IKJET˙INSAYISALOLARAK˙INCELENMES˙IVEOPT˙IM˙IZASYONU
Akc¸ayo¨z, Eray
Yu¨ksekLisans,HavacılıkveUzayMu¨hendislig˘i Bo¨lu¨mu¨
TezYo¨neticisi : Prof. Dr. ˙IsmailH.Tuncer
Eylu¨l2008,73sayfa
Bu c¸alıs¸mada, NACA 0015 kanat kesidi u¨zerine sentetik jet uygulanarak aktif akıs¸ kon-
trolu¨ sayısal olarak incelenmis¸tir. NACA 0015 kanat kesidi u¨zerinde olus¸an zamana bag˘lı,
tu¨rbu¨lanslı akıs¸ Navier-Stokes akıs¸ c¸o¨zu¨cu¨ kullanılarak hesaplanmıs¸tır. Tu¨mhesaplamalarda
Spalart-Allmaras tu¨rbu¨lans modeli kullanılmıs¸tır. Zamana bag˘lı akıs¸ hesaplamaları, Parallel
Virtual Machine ku¨tu¨phanesi kullanılarak paralel olarak yapılmıs¸tır. Sentetik jet, Navier-
Stokesakıs¸c¸o¨zu¨cu¨su¨nebirsınırkos¸uluolarakeklenmis¸tir. Eniyiles¸tirmec¸alıs¸malarında,sen-
tetik jete ait parametrelerin eniyiles¸tirilmesi sag˘lanarak kaldırma ve su¨ru¨klenme katsayıları
oranının maksimum deg˘eri alması hedeflenmis¸tir. Sentetik jet parametrelerinin farklı hu¨cum
ac¸ılarındaeniyiles¸tirilmesiic¸inYanıtYu¨zeyYo¨ntemikullanılmıs¸tır. Kaldırmavesu¨ru¨klenme
katsayıları oranı sentetik jetin hızı, konumu, ac¸ısı ve frekansı kullanılarak eniyiles¸tirilmis¸tir.
Eniyiles¸tirme c¸alıs¸maları jet gu¨c¸ katsayısının deg˘eri sabit tutularak gerc¸ekles¸tirilmis¸tir. Jet
c¸ıkıs¸ınıngenis¸lig˘ibag˘ımlıbirparametreolarakkullanılmıs¸tır.
Eniyiles¸tirmec¸alıs¸malarında, sentetik jetinhızıvekonumunun dig˘erjetparametrelerine go¨re
daha baskın oldug˘u go¨ru¨lmu¨s¸tu¨r. En uygun sentetik jet ac¸ısının hu¨cum ac¸ısı arttıkc¸a arttıg˘ı
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go¨zlemlenmis¸tir. Akıs¸ ayrılmasının oldug˘u durumlarda, en uygun sentetik jet konumunun
hu¨cum ac¸ısı arttıkc¸a kanat hu¨cum kenarına kaydıg˘ı go¨ru¨lmu¨s¸tu¨r. Eniyiles¸tirme c¸alıs¸maları,
kanatu¨zerineuygulanan sentetikjetino¨zellikleperdo¨vites ac¸ısındanbu¨yu¨khu¨cumac¸ılarında
akıs¸ ayrılmasını geciktirdig˘ini ve kaldırma ve su¨ru¨klenme katsayıları oranını o¨nemli o¨lc¸u¨de
arttırdıg˘ını go¨stermis¸tir. Kanat u¨zerindeki akıs¸ın yu¨zeye yapıs¸ık oldug˘u durumlarda sentetik
jetindahaazetkilioldug˘ugo¨zlemlenmis¸tir.
Anahtar Kelimeler: Akıs¸ Kontro¨lu¨, Sentetik Jet, Eniyiles¸tirme, Paralel C¸o¨zu¨m, Yanıt Yu¨zey
Yo¨ntemi
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Tomymarvelousfamily
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ACKNOWLEDGMENTS
Iwouldliketothankmysupervisor,Prof. Dr. ˙IsmailH.Tuncerforhisgreatcareandguidance
throughout mystudies.
Iwouldliketothankalljurymembersfortheiradvicesandcorrections.
IwouldalsoliketothankEnginErler,forherendlessfriendship andsupport.
Forhisassistance, Iamgrateful tothank Dr. Mustafa Kaya. Thankyouforyoursupport and
helpwithoutconcerning anytimelimitation.
I want tostate mythanks to Hakan Tiftikc¸ifor reviewing my thesis and answering all of my
questions.
IalsowanttostatemythankstoYes¸imKubilayforherenglishcorrections.
ThankstoMETU,AerospaceEngineeringDepartmentforprovidingmeaparallelcomputing
environment.
Ifinallywouldliketothankanyonewhohavesupported mythesiseffortinanyway.
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