流体力学中科大 英文版.ppt

FluidMechanics,Introduction,AboutmeAboutthecourseScopeHistoryUnit,Teacher,Name:XishengLuoContact3601951,360124213866682799xluoxsluoQQ:1017414546CV:89059406STUERWTH-USTC,Golfball:smoothorrough?,Car:changeofshape,0.8,Car,0.6,0.45,Car,0.3,0.2,0.137,Airplane:lift?,Textbook,高等教育出版社丁祖荣流体力学，上中清华大学出版社张兆顺崔桂香流体力学北京大学出版社吴望一流体力学中国科学技术大学童秉纲等流体力学,Schedule,IntroductionPropertiesKineticsDynamicsDimensionlessStaticsPotentialflowViscousflowCompressibleflowTrend,Requirement,ListenExerciseExamQuestion,ScopeofFluidMechanics(1),Fluids:gasesandliquids,waterandairmostprevalentindailyexperienceExamples:Flowinpipesandchannels-airandbloodinbodyAirresistanceordrag-windloadingProjectilemotion-jets,shockwavesLubrication-combustionIrrigation-sedimentationMeteorology-oceanography,ScopeofFluidMechanics(2),Usedinthedesignof:Watersupplysystem-wastewatertreatmentDamspillways-valves,flowmetersShockabsorbers,brakes-automatictransmissionsships,submarines-breakwaters,marinasAircrafts,rockets-computerdiskdrivesWindmills,turbines-pumps,HVACsystemsBearings-artificialorgansSportitems:Golfballs*YatchsRacecars*hangglidersSurfboards,Asfishhabitat.,Forreptilehabitat.,Formammalshabitat.,Forinsectstowalkonasurface.,Inriversandstreams.,Atornado.anatmosphericvortex,Airtobreathe.,Mixing(asinsoups),Airasatransportationmean.,Watersurfaceforboating.,Flowofairaroundcars.,Gasesusedaspropulsionagents,Airresistancetoslowdownalanding,Smokefromhomesorindustries.,Historicaldevelopment(1),Ancientcivilizations:irrigation,shipsAncientRome:aqueducts,baths(4thcenturyB.C.)AncientGreece:Archimedesbuoyancy(3rdcenturyB.C.)Leonardo(1452-1519):experiments,researchonwaves,jets,eddies,streamlining,flying,Historicaldevelopment(2),Newton(1642-1727):lawsofmotion,lawofviscosity,calculus18thcenturymathematicians:solutionstofrictionlessfluidflows(hydrodynamics)17th&18thcenturyengineers:empiricalequations(hydraulics)Late19thcentury:dimensionlessnumbers,turbulence,Historicaldevelopment(3),Prandtl(1904):proposesideaoftheboundarylayerFlowfieldsoflow-viscosityfluidsdividedintotwozones:Athin,viscosity-dominatedlayernearsolidsurfacesAneffectivelyinviscidouterzoneawayfromboundariesExplainsparadoxesAllowanalysisofmorecomplexflows20thcentury:hydraulicsystems,oilexplorations,structures,irrigation,computerapplications,Historicaldevelopment(4),Beginningof21stcentury:NocompletetheoryforthenatureofturbulenceStillacombinationoftheoryandexperimentaldataReferences:Rouse&Ince:HistoryofHydraulics,Dover,NY1963Rouse:HistoryofHydraulicsintheUnitedStates(1776-1976),UofIowa,1976Levy,E.,ElAguaSegunlaCiencia,CONACYT,Mexico,1989,FluidMechanicsOverview,Gas,Liquids,Statics,Dynamics,Air,He,Ar,N2,etc.,Water,Oils,Alcohols,etc.,Viscous/Inviscid,Steady/Unsteady,Compressible/Incompressible,Laminar/Turbulent,Flows,Compressibility,Viscosity,VaporPressure,Density,Pressure,Buoyancy,Stability,Chapter1:Introduction,FluidDynamics:RestofCourse,SurfaceTension,Fluid,Mechanics,Propertiesoffluids,Distinctionbetweenasolidandafluid(1),MoleculesofsolidclosertogetherthanthoseoffluidSolid:intermolecularforceslargerthaninfluidElasticsoliddeformsunderloadrecoversoriginalstatewhenunloadedPlasticsolid:deformsundersufficientloadcontinuesdeformingaslongasloadisapplieddoesnotreturntooriginalstate,Distinctionbetweenasolidandafluid(2),IntermolecularforcesinfluidnotlargeenoughtoholdelementstogetherFluidflowsunderslighteststressandcontinuesflowingaslongasstressispresent,Distinctionbetweenagasandaliquid(1),Fluids:gasesorliquidsGAS:MoleculesfartherapartVerycompressibleTendstoexpandindefinitelyLIQUID:RelativelyincompressibleIfexternalpressureremoved,doesnotexpandMayhaveafreesurface(subjecttoitsownvaporpressure),Distinctionbetweenagasandaliquid(2),VAPOR:GaswhoseTandPveryneartheliquidphaseSteamisavapor,statenearthatofwaterGAS:Super-heatedvapor,farawayfromliquidphaseVolumeofgasorvaporgreatlyaffectedbyTandPThermodynamicsStudyofheatphenomenaImportantifsignificantTorphasechangesinvolved,Distinctionbetweenagasandaliquid(3)