Sound-Flow Interactions

ISBN-13: 9783540433323 / Angielski / Twarda / 2002 / 286 str.

Y. Auregan; A. Maurel; V. Pagneux

Opis

TheCargeseSummerSchool Sound ?owinteractions washeldinthe- stitutd EtudesScienti?quesdeCargeseinCorsica, Francefrom19thJune to1stJuly,2000. Theunderstandingofsoundand?owinteractionshasmadesomerema- ableprogresssincethepioneeringworksoftheRussianandBritishschools, inthe1950s. Inaddition, thegrowingavailabilityduringthepast10years ofsophisticatedcomputer/electronics/materialstechniquesallowsforthe- velopmentofagrowingnumberofapplicationsaswellasthepossibilityof addressingnewfundamentalproblems. Thecouplingbetweenacousticwaves and?owmotionisbasicallynonlinear, sothatthesoundpropagationand generationismodi?edbythe?owandthe?owcanalsobemodi?edbythe sound. Asaresult, thisproblemisinvestigatedinmanydi?erentscienti?c communities, suchasappliedmathematics, acousticsand?uidmechanics, amongothers. Inouropinion, thetimehadcometotrytogatherthe- searchersinthedi?erentcommunitiestogetherinatutorialenvironemnt. So, thisschoolbroughttogetherworldwidespecialistsinordertopresentvarious aspectsofsound ?owinteractions, andshareexpertiseandmethodologiesso astopromotecross-fertilisation. ThebasicknowledgeintheareaisintroducedbyA. HirschbergandC. Schram. Hepresentstheaeroacousticsofinternal?owinaverylivelyway withalotofillustrationdevices. Heintroducesaeroacousticanalogiesand applicationslikemusicalinstruments, theRijketube, speechproductionetc. M. S. Howeintroducesthetheoryofvortexsoundinaverydidacticway. From Lighthill sacousticanalogy, heshowshowvorticityandentropy?uctuations canbeseenassourcesofsound. Then, usingthecompactGreen sfunctions, heshowshowtocomputethevortexsound. Asanexampleofthemethod presented, heappliesthistheorytopressuretransientsgeneratedbyhi- speedtrains. F. Lundgivesthebasicequationsofsound ?owinteractions. Thenheintroducesveryclearlythescatteringofsoundbecauseofvorticity andgivesthemostrecentresultsonultrasoundpropagationthroughadis- dered?ow. V. Ostashevpresentsgeometricalacousticsinmovingmediaand theimportantpracticalproblemofsoundpropagationinturbulence(at- sphere, ocean). A. Fabrikantexaminestheplasma hydrodynamicsanalogies includingtheresonantwave-?owinteractioninshear?ows, wavesofnegative VI Preface energyandover-re?ectionandacousticoscillatorsin?uid?ows. P. J. Mor- sondescribesthedynamicsofthecontinuousspectrumwhichoccursinshear ?ow. Theresultsareinterpretedinthecontextofin?nitedimensionalHam- toniansystemstheory. G. Chagelishvilipresentsnewlinearmechanismsof acousticwavegenerationinsmoothshear?owsusinganon-modalstudy. N. Peakepresents?uid structureinteractionsinthepresenceofmean?ows, includingtheproblemsofinstabilityandcausality. Finally, W. Lauterborn presentsnonlinearacousticswithapplicationstosonoluminescenceandto acousticchaos. InthisCargeseSummerSchool,54studentsfrom12nations, and11l- turersfrom7nationsparticipated. Aknowledgements. TheSummerSchoolandthispublicationwouldnot havebeenpossiblewithout: nancialsupportfromtheEuropeanUnion, theCentreNationaldela RechercheScienti?que, theMinisteredesA?airesEtrangeres, theM- isteredel EducationNationale, delaRechercheetdelaTechnologieand theGroupementdeRecherche Turbulence; the guidance of Elisabeth Dubois Violette, director of the Institut d EtudesScienti?quesdeCargese; thehelpofChantalAriano, NathalieBedjai, BrigitteCassegrain, Pierre- EricGrossiandthewholeteaminpreparingandhostingofthisschool. Finally, wewishtothankthelecturersforgivingsomuchtimeinprep- ingthelecturesandwritingthemup, aswellasmakingthemselvesavailable fordiscussionsduringtheschool. 1 LeMans, Paris, Lyon YvesAuregan, 2 September2001 AgnesMaurel, 1 VincentPagneux, 3 Jean-Fran, coisPinton . 1 Laboratoired Acoustiquedel UniversiteduMaine, UMRCNRS6613, Av. OMessiaen,72085LeMansCedex9, France 2 LaboratoireOndesetAcoustique, UMRCNRS7587, ESPCI,10rueVauquelin,75005Paris, France 3 LaboratoiredePhysique, UMRCNRS1325, EcoleNormaleSuperieuredeLyon,46alleed Italie,69007Lyon, France Preface VII SomeofthelecturersoftheCargeseSchool, fromlefttoright: M. S. Howe, A. Hirschberg, P. Morrison, W. Lauterborn, V. Ostashev, A. Fabrikant, N. Peake, T. Colonius(PhotoC. Schram) SomeoftheparticipantsoftheCargeseSchool(PhotoC. Schram) TableofContents APrimitiveApproachtoAeroacoustics AvrahamHirschberg, ChristopheSchram. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 FluidDynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 Lighthill sAnalogy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4 JetNoise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 Thermo-Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 AcousticalEnergy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7 Rijke-Tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8 Vortex-SoundTheory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9 ChoiceoftheGreen sFunction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 10 Howe sEnergyCorollary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 11 TheOpenPipeTerminationofanUn?angedPipe . . . . . . . . . . . . . . 21 12 Whistler-NozzleandHumanWhistling . . . . . . . . . . . . . . . . . . . . . . . . 25 13 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 LecturesontheTheoryofVortex Sound MichaelS. Howe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1 AerodynamicSound. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1. 1 Lighthill sAcousticAnalogy(1952). . . . . . . . .

Spis treści

A Primitive Approach to Aeroacoustics.- Lectures on the Theory of Vortex-Sound.- Sound—Vortex Interaction in Infinite Media.- Geometrical Acoustics in Moving Media.- Sound Propagation and Scattering in Random Moving Media.- Plasma—Hydrodynamic Analogy for Waves and Vortices in Shear Flows.- New Linear Mechanisms of Acoustic Wave Generation in Smooth Shear Flows (Nonmodal Study).- Singular Eigenfunctions and an Integral Transform for Shear Flow.- Structural Acoustics with Mean Flow.- Nonlinear Acoustics and Acoustic Chaos.

Blurb

The coupling between acoustic waves and fluid flow motion is basically nonlinear, with the result that flow and sound modify themselves reciprocally with respect to generation and propagation properties. As a result this problem is investigated by many different communities, such as applied mathematics, acoustics and fluid mechanics. This book is the result of an international school which was held to discuss the foundation of sound--flow interactions, to share expertise and methodologies, and to promote cross-fertilization between the different disciplines involved. It consists essentially of a set of pedagogical lectures and is meant to serve not only as a compact source of reference for the experienced researcher but also as an advanced textbook for postgraduate students, and nonspecialists wishing to familiarize themselves in depth, at a research level, with this fascinating subject.