Table Of Content100 NotesonNumericalFluidMechanicsandMultidisciplinaryDesign(NNFM)
Editors
E.H. Hirschel/München
W. Schröder/Aachen
K. Fujii/Kanagawa
W. Haase/München
B. van Leer/Ann Arbor
M.A. Leschziner/London
M. Pandolfi/Torino
J. Periaux/Paris
A. Rizzi/Stockholm
B. Roux/Marseille
Y. Shokin/Novosibirsk
100 Volumes of ‘Notes on
Numerical Fluid Mechanics’
40 Years of Numerical Fluid Mechanics and
Aerodynamics in Retrospect
Ernst Heinrich Hirschel
Egon Krause
(Editors)
ABC
Prof.Dr.E.H.Hirschel
Herzog-Heinrich-Weg 6
85604Zorneding
Germany
E-mail:[email protected]
Prof.Dr.E.Krause
RWTHAachen
Aerodynamisches Institut
Wüllnerstr. 5a
52062Aachen
Germany
E-mail:[email protected]
ISBN 978-3-540-70804-9 e-ISBN 978-3-540-70805-6
DOI 10.1007/978-3-540-70805-6
Notes on Numerical Fluid Mechanics
and Multidisciplinary Design ISSN 1612-2909
LibraryofCongressControlNumber:2009921827
(cid:2)c 2009Springer-VerlagBerlinHeidelberg
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NNFM Editor Addresses
Prof.Dr.ErnstHeinrichHirschel Prof.Dr.MaurizioPandolfi
(GeneralEditor) PolitecnicodiTorino
Herzog-Heinrich-Weg6 DipartimentodiIngegneria
D-85604Zorneding AeronauticaeSpaziale
Germany CorsoDucadegliAbruzzi,24
E-mail:[email protected] I-10129Torino
Italy
Prof.Dr.WolfgangSchröder E-mail:pandolfi@polito.it
(DesignatedGeneralEditor)
RWTHAachen Prof.Dr.JacquesPeriaux
LehrstuhlfürStrömungslehreund 38,BoulevarddeReuilly
AerodynamischesInstitut F-75012Paris
Wüllnerstr.zw.5u.7 France
52062Aachen E-mail:[email protected]
Germany
E-mail:offi[email protected] Prof.Dr.ArthurRizzi
DepartmentofAeronautics
Prof.Dr.KozoFujii KTHRoyalInstituteofTechnology
SpaceTransportationResearchDivision Teknikringen8
TheInstituteofSpace S-10044Stockholm
andAstronauticalScience Sweden
3-1-1,Yoshinodai,Sagamihara E-mail:[email protected]
Kanagawa,229-8510
Japan Dr.BernardRoux
E-mail:fujii@flab.eng.isas.jaxa.jp L3M–IMTLaJetée
TechnopoledeChateau-Gombert
Dr.WernerHaase F-13451MarseilleCedex20
HöhenkirchenerStr.19d France
D-85662Hohenbrunn E-mail:[email protected]
Germany
E-mail:offi[email protected] Prof.Dr.YuriiI.Shokin
SiberianBranchofthe
Prof.Dr.BramvanLeer RussianAcademyofSciences
DepartmentofAerospaceEngineering InstituteofComputational
TheUniversityofMichigan Technologies
AnnArbor,MI48109-2140 Ac.LavrentyevaAve.6
USA 630090Novosibirsk
E-mail:[email protected] Russia
E-mail:[email protected]
Prof.Dr.MichaelA.Leschziner
ImperialCollegeofScience
TechnologyandMedicine
AeronauticsDepartment
PrinceConsortRoad
LondonSW72BY
U.K.
E-mail:[email protected]
Preface I
Aircraft concepts are always driven by the requirements of the desired mis-
sion. A different purpose for the use of the aircraft consequently results in
a different design. Therefore, depending on the intended outcome, conflict-
ing requirements need to be fulfilled, for example, efficient cruise speed and
greatercargocapabilities,incombinationwithshorttake-offandlandingfield
lengths, or high speed and agility combined with variable payload demands.
Due to the highly complex, non-linearphysicalenvironmentin which aircraft
operate, this task demands that the most advanced methods and tools are
employed, to gain the necessary understanding of flow phenomena, and to
exploit the flow physics to achieve maximum aircraft efficiency.
Inthenaturalsciences,researcherstrytocreateandextendhumanknowl-
edge by understanding and explaining the mechanisms of physical processes.
In engineering, a designer is limited by certain requirements, and in order to
fulfil these requirements the necessarytechnical tools need to be designed.In
general,for a given problem the correspondingscientific or technical solution
issought.Inordertosuccessfullyadvancefromaproblemtowardsasolution,
three main methods may be used. The two classical methods include theory
and experiment, which are now being complemented by a third method, de-
scribedasnumericalsimulation.Theexperimentalapproachisbasedonphys-
ical observation,measurementof relevantvalues, and methodical variationof
the subject matter. For example, such experiments are used to gain a phys-
ical understanding as well as to validate and investigate design alternatives.
In aerodynamics, experimental research is carried out by wind tunnel and
flight testing. However, in the theoretical approach, certain correlations be-
tweenphysicalobservationandmathematicalprinciplesarehypothesized,and
a corresponding mathematical formulation is developed, which describes the
main mechanisms of the observedphenomena. A typical example of theoreti-
cal design methods is the Lifting-Line-Theory, developed by Ludwig Prandtl
in 1918, which is itself based on potential theory.
With the progressive innovations in computer technology over the past
decades,accompaniedby correspondingalgorithmic developments,numerical
VIII Preface I
simulationhasmaturedfromascientificpeculiaritytoatoolapplicabletothe
broadspectrum,fromscientificinvestigationstoproduct-orientedengineering
design. Numerical simulation emulates physical processes by solving systems
of differential equations, and can be interpreted as a complementary element
to experimentation and theoretical consideration. Furthermore, as it involves
elements of both experimentation and theoretical consideration, it may be
regarded as the bridge between experiment and theory.
Numerical simulation is inherently interdisciplinary, as physics, mathe-
matics, and informatics are all equally concerned. In 1755, Leonhard Euler
proposed a set of non-linear partial differential equations, which describe the
conservationofmassandmomentumforaninviscidfluid.Morethan50years
later,ClaudeNavierin1822,andGeorgeStokesin1845,independently intro-
ducedviscoustransportintotheseequations.Thiswassubsequentlyextended
to include the energy equation. After being cast into the so-called conserva-
tion form to capture flow discontinuities, the differential equations proposed
now form the basis of numerical simulation in fluid dynamics today.
A direct solution of these differential equations is not generally feasible,
and analytical solutions can only be obtained in unique cases, which are of
limited practical interest. Essentially, there are two major routes that are
followed to solve these equations: Either the equations will be further sim-
plified, so that solutions are easier to obtain, which for example, resulted in
the establishment of the potential theory of aerodynamics. Or the original
exactequationswillbe solvedonlyapproximatelyby establishingandsolving
a corresponding set of discrete algebraic equations, which is numerical flow
simulation. This process has been termed “Numerical Fluid Mechanics,” re-
spectively “Computational Fluid Dynamics” (CFD), since the solution of the
algebraicsystemofequationsrequirestheuseofhighperformancecomputers.
For aerodynamics, the development of Computational Fluid Dynamics is
particularlydrivenbyaninterestintransonicflows,whichevolvedintheearly
days of commercialjet aviationwhen the transonic dragrise phenomenon re-
ceived particular attention. The solution of the Euler equations was essential
forCFDresearchinthe1980s.Thisiscomparabletothe1990s,whichwasthe
decadeinstrumentaltosolvingthe Navier-Stokesequations.Aprojectforthe
development and validation of a reliable and efficient numerical tool for the
aerodynamic simulation of a complete aircraft was initiated under the lead-
ership of the German Aerospace Center (DLR) which would meet industrial
implementationrequirements.AsoftwaresystemtitledMEGAFLOWwasde-
veloped, and incorporatedthe block-structured Navier-Stokescode FLOWer,
and the unstructured Navier-Stokes code TAU. Both codes have reached a
high level of maturity and in cooperation with the DLR are intensively used
by the German Aerospace Industry and its European partners in the design
processes of new aircraft.
Numericalsimulationhas identifiedtwochallengesfor future researchand
development. The first challenge is to extend the range of applicability of
CFD methods. Furthermore, the second challenge is directly concerned with
Preface I IX
the cost of applying CFD methods in the design process within multidisci-
plinarynumericalsimulationandoptimizationtools.Forinstance,inorderto
determine the static and dynamic loads required for structural design, hun-
dreds of thousands of aerodynamic load cases need to be evaluated.
The tremendous progress achieved in numerical simulation over the past
decades would not have been possible without the substantial increase in
computational power. Therefore, in addition to the other notable theories of
numerical simulation, the so-called Moore’s Law developed in the 1960s by
Gordon Moore, describes the continuum of increasing computational power.
More specifically the theory hypothesizes that within 30 years computational
power would increase by a factor of 33,000; and a computational job, which
today would require 30 years, will in the future take only 8 hours to process.
To further meet the challenges of numerical simulations, as hypothesized by
Moore,there will be opportunities to make use ofthe upcoming greatercom-
putational capabilities. If efficiently implemented, this may open up the pos-
sibility to “flight-test” a simulated aircraft with all of its multidisciplinary in-
teractionsinavirtualenvironment.Thiswouldhelptoincreaseperformance,
reduce risk and to promote cost effectiveness in aircraft design processes by
notonlycompilingallthedatarequiredfordevelopmentandcertificationwith
a guaranteed accuracy, but also in a significantly reduced time frame. Thus,
within the framework of numerical simulation and the methods of aircraft
conceptual design, development and detailed design, the capabilities will be
revolutionized.
There has been dramatic progress over more than 30 years in developing
and applying numerical methods successfully in research and development.
This success has been accompanied, stimulated and documented not only by
appropriateworkinggroups,workshopsandinternationalconferencesbutalso
by initiating in 1978 the book series “Notes on Numerical Fluid Mechanics.”
This series,as wellasearlierthe GAMM Committee onNumericalFluid Me-
chanics with its conferences and workshops, originated at the DLR (at that
time DFVLR) in Cologne-Porz.The present volume, produced 30 years after
the series’firstpublication,underlinesthe capabilitiesoftodaysmethods and
tools and provides an impressive display of the expansive range of applica-
tionsforscience,engineeringandparticularlyforaircraftresearch,designand
development.
Cologne Prof. Dr. Joachim Szodruch
October 2008 Member of the Executive Board
DLR German Aerospace Center
Preface II
Over the last three decades, Computational Science and Engineering evolved
into a “third pillar” of scientific research alongside theory and experiment.
The discipline ofComputationalScience,onthe onehand,enhancesscientific
investigationby enabling theorists and practitionersto build and test models
ofcomplexphenomena,yieldingnewinformation,innovationandfreshinsight
into the research process that is not available through other means. On the
other hand, it is a discipline sui generis that unlocks new areas of research,
e. g., where experiments are impossible, too dangerous or forbidden. Essen-
tial contributions from Computational Science can be expected in a variety
of fields of interest. They will lead to major advances in scientific research,
leading to importantindustrialinnovationand havinga highsocietalimpact.
The interplay between mathematical modeling and algorithm develop-
ment/implementation is the driving force for Computational Science and
Engineering. The availability of sophisticated numerical methods like Com-
putational Fluid Dynamics is crucial to enhance the usability of modern su-
percomputers as for example the massively parallel IBM BlueGene systems.
It’s one of the aims of the Jülich Supercomputing Centre to cooperate with
all scientific communities to enable important new simulation software for
supercomputing.
The acceleration in the development of parallel supercomputers together
with the advancing requirements of computational scientists and engineers
with respect to application,memory,data storage,anddata transfer capabil-
ities,makesitincreasinglydifficult forsingle institutions to providecontinual
funding forlatesttop-rankedsystemsinevershorterperiods.Apossiblesolu-
tionisthecreationofnetworksorallianceswhichagreeonclosecollaboration
and internal innovation cycles. With the creation of the Gauß Centre for Su-
percomputing in 2006,Germany createda new and powerful structure for its
three national supercomputing centers, the Leibniz Supercomputing Centre
atGarching/München,the Supercomputing CentreJülich,andthe HighPer-
formance Computing Center Stuttgart, to take a leading role in Europe. The
GaussCentreforSupercomputingrepresentsGermanyasasinglelegalentity
XII Preface II
in the European supercomputing infrastructure initiative PRACE (Partner-
ship for Advanced Computing in Europe) which aims at the creation and
sustainedoperationofapan-EuropeanTier-0supercomputingserviceandits
fullintegrationintotheEuropeanHPCecosystemfrom2010on,asoneofthe
list items of the European Strategy Forum on Research Infrastructures, ES-
FRI.WithintheframeworkofPRACE,Germany’sForschungszentrumJülich
aspires to host the first European supercomputing centre with Petaflop/s
capability in 2009/2010.
The potential of CFD applications on high-end HPC systems can be il-
lustrated using a computation performed recently by CERFACS (Toulouse,
France) on an IBM BlueGene/L machine as reported in the “Scientific Case
for European Petascale Computing” by the HPC in Europe Taskforce. This
simulation of the ignition of a helicopter gas turbine (about 20 millions nu-
merical cells) is one of the most complex large eddy simulations in turbulent
combustion and took 60,000 CPU hours on 1024 processors (about 2.5 days
of wall clock time). In order to reach a steady state regime, 100 to 200,000
additional CPU hours are required which can only be achieved on Petaflop
systems.
The Notes on Numerical Fluid Mechanics and Multidisciplinary Design
have been a most faithful companion of the field in the past. The Gauss
Centre for Supercomputing is convinced that the NNFM will be a complete
success in the forthcoming Petaflop Era as well.
Jülich Prof. Dr. Achim Bachem
October 2008 Gauß Centre for Supercomputing,
Chairman of the Board of Directors
of the Research Centre Jülich
