FluidMechanics

2023/6/111PrefaceContentsTeachingContents——

InClassroomExperimentalProjects——

InTeachingLabTotalhours:54Classroomteachinghours:48Practicehours:62023/6/112TeachingContents

(1)PartA

(Totalhours:36)A1Introduction(4hours)A2Fluidstatics(6hours)A3Fluidkinematics(6hours)A4Fluiddynamics(6hours)A5Laminarflow,turbulentflowandenergyloss(8hours)A6Pipeflowandcalculationofpipeline(4hours)A7Similaritytheoryanddimensionalanalysis(2hours)Fundamental2023/6/113PartB

(Totalhours:8)B1Streamfunctionsandpotentialfunctions,frictionlessirrotationalflow(4hours)B2Boundarylayertheoryandflowpastbody(4hours)PartC

(Totalhours:4)C1ResaerchprogressinFluidMechancis(1hour)C2Modernflowmeasurementtechnologies(1hour)C3IntroductiontonumericalsimulationofturbulenceflowandcommercialsoftwaresofCFD(2hours)TeachingContents

(2)ExtendedcontentsFundamental2023/6/114PartAandPartBarethefoundationofFluidMechanics,PartCistheextendedcontentsandrefertosomepracticalproblems.Thiscoursealsopaysmuchattentiontotheprevalenceofmodernfluidmechanics,forexample,theintroductiontothetheoryofturbulenceboundarylayerandthesketchofcomputationalfluiddynamics(CFD)willhelpyourfurtherapplicationsafteryourgraduation.TeachingContents

(3)2023/6/115ExperimentalProjects(1)In-class(Required)(Totalhours:6)E1Hydrostatics(1hour)E2VelocitymeasurementwithPitottube(1hour)E3FlowmeasurementwithVenturitube(1hour)E4VerificationofBernoulliequation(1hour)E5Reynoldsexperiment(1hour)E6Measurementoffrictionlosscoefficientforcircularpipeflow(1hour)2023/6/116ExperimentalProjects(2)After-class(Totalhours:6-8)E1Liquidviscositymeasurement(1hour)(Optional)E2Demonstratingexperimentaboutflowpatternandstreamline(1hour)(Required)E3Measurementoflocallosscoefficientforcircularpipeflow(1hour)(Required)E4DemonstratingexperimentaboutSiphonprinciple(1hour)(Required)E5Demonstratingexperimentaboutflowaroundairfoilandcylinder(1hour)(Required)E6Demonstratingexperimentaboutvortexformation(1hour)(Required)E7Self-designingexperiments(1hour)(Optional)2023/6/117Textbook

FrankM.White.FluidMechanics.McGrawHillHigherEducation,7thRevisededition,2010.22023/6/118ReferencesE.JohnFinnemore,JosephB.Franzini.FluidMechanicswithEngineeringApplications.McGraw-HillHigherEducation,10thRevisededition,2001.102023/6/119ReferencesJinXiaohong,LiYuanhui.FluidMechanics(bilingualTeaching).Beijing:ChinaPowerPress,2011.92023/6/11105%attendance10%homework10%requiredexperiments5%optionalexperiments70%finalexamGrades2023/6/1111Chapter1Introduction

Whenyouthinkaboutit,almosteverythingonthisplaneteitherisafluid

ormoveswithinornearafluid.

——FrankM.WhitePreliminaryRemarksFluidcanbefoundalmosteverywhereontheearth!2023/6/1112OverviewofFluidMechanics

Theconceptof

fluid

Theprimaryphysicalpropertyoffluid

Studyobjectsof

FluidMechanics

Thenatureofthesubjectof

FluidMechanicsTasksof

FluidMechanics

Studyapproachesof

FluidMechanics

Importance(position)ofthecourse

Historyof

FluidMechanicsThefollowingaspectswillbediscussed:2023/6/1113Theconceptofafluid

Asolidcanresistashearstressbyastaticdeformation.Afluidcannotresistashearstressbyastaticdeformation.Anyshearstressappliedtoafluid,nomatterhowsmall,willresultinmotionofthatfluid.Thefluidmovesanddeformscontinuouslyaslongastheshearisapplied.Introduction2023/6/1114Isithasafixedvolume？Canitformafreesurface？Isiteasytobecompressed？FluidgasnonoyesliquidyesyesnoFluidity？

FluidSolidyesnoTheprimaryphysicalpropertyoffluid2023/6/1115Fluidmechanicsisanimportantbranchofmodernmechanics，It’sasciencethatstudiesfluid’sbalance(Fluidstatics),mechanicalmovementlaws(FluidKinematics)

andtheinteractionbetweenfluidandtheboundaries

(FluidDynamics),whichmaybeeithersolidsurfacesorinterfaceswithotherfluids.Itmainlyascertainsthedistributionofspeedandpressure,energylossandtheinteractionforceandthemomentbetweenfluidandboundary.

IntroductionStudyObjectsofFluidMechanics(1)2023/6/1116Waterandairareresearchedmostlyinfluidmechanics.Besidesthese,fluidalsoincludesvaporasworkmediuminturbine,lubeoil,waterwhichmixingwithmudandsand,blood,meltingmetalandthegaswithcomplicatedcomponentscomingfromburning,plasmasunderhightemperaturecondition,etc.StudyObjectsofFluidMechanics(2)Stationaryboundaries：riverbed,pipewall,building,etc；

Movingboundaries：aircraft,ship,runner,etc.Typesofboundary2023/6/1117MechanicsResearchobject

Thecarrierofmechanicalproblems

FluidMechanicsFluidLiquidWaterMechanicsThreeconservationlawsHydraulicsIntroductionLiquidisthemainresearchobject;Mainlyfocusonengineeringapplications;SuitableforstudentsinHydraulicEng.,

CivilEng.ThenatureofthesubjectofFluidMechanicsConservationofmass,momentumandenergy2023/6/1118Fluidmechanicsisnotonlyanage-oldsubject,butalsoanewfashionsubjectwhichcanberesearchedonquitewidelyfields.Therearemanyquestionsaboutfluidmechanicsinthesedepartments,suchasinaviation,spaceflight,navigation,

astronomicalweather,physicalgeography,waterconservancyandhydropower,heatenergyrefrigeration,buildingconstructionandenvironmentalprotection,petroleumandchemicalengineering,transportingairandliquid,

combustionandexplosion,metallurgyandmining,biologyandsea,warindustryandnuclearenergy,machinebuilding,mechanicalengineering,

etc.TasksofFluidMechanicsIntroductionEngineeringfieldsanddisciplinesrelativetoFluidMechanics2023/6/1119Vortexcreatedbythepassageofanaircraftwing,revealedbycolouredsmokeTurbulenceinthetipvortexfromanairplanewingEngineeringfieldsrelativetoFluidMechanics2023/6/1120aviationspaceflightnavigationRocketlaunchingfountain2023/6/1121Axial-flowfan¢rifugalpumpfanpumpimpeller2023/6/1122Multi-stageaxial-flowcompressormodelCompressor

2023/6/1123Waterturbineandelectricalgeneratorcut-awayview

Kaplanturbine

runnerandbladehydropower2023/6/1124Modelplanetestedinawindtunnel

CarwindtunneltestAirflowpastanaerofoilCoolingfan2023/6/1125TheThreeGorgesDamphotographedbysatelliteoftheUnitedStatesHydraulicEngineeringwaterconservancyprojectDujiangyancomprehensiveengng2023/6/1126TyphoonTornado:Arotatingcolumnofairusuallyaccompaniedbyafunnel-shapeddownwardextensionofacumulonimbuscloudandhavingavortexseveralhundredyardsindiameterwhirlingdestructivelyatspeedsofupto500miles(800km)perhour.TyphoonTyphoon:AtropicalcycloneoccurringinthewesternPacificorIndianoceans.Tornado2023/6/1127vortexformedintherearofahigh-speedtrainboilingmudnearaVolcaniccraterTornado2023/6/1128Hurricane“Elena”intheGulfofMexico

Weathernephogram(云圖):vorticesinatmosphereContourofthehurricane"Sandy"seenfromspaceHurricane2023/6/1129Weathernephogram:vorticesinatmosphereAirvortexstreetoverthenorthernseaofJapanWeatherCFD—supercomputer2023/6/1130Dewanddrop2023/6/1131Surfacetensionsoapbubblewater-drop2023/6/1132volleyballfootballtennisswimmingrowingdiscusthrowgolfballracecarracingjavelintabletennisbadmintonMostsportsarerelatedtoFluidMechanics2023/6/1133Golfballwithsmooth&roughsurface,Whichisbetter？Question2023/6/1134

GolforiginatedinScotlandinthe15thCentury.Itwasthoughtintheearlydaysthatthegolfballwithsmoothsurfacehadsmallflightresistance,sotheballwasmadeinleather.Itwasfoundafterwardsthatanoldballwithmanyscratchesonitssurfacecouldflyfartherthananewballwithsmoothsurface.ThismysterywasnottobesolveduntiltheboundarylayertheorywasestablishedbyL.Prandtlinthe20thCentury.

Thepresent-daygolfhasalotofpitsonit’ssurface,andtheflightdistanceofaroughsurfaceballis5timesfartherthanasmoothballwhentheyhavethesamesizeandweight.2023/6/1135EarlygolfballPresent-daygolfwakezonewakezone2023/6/1136DisciplinesRelativetoFluidMechanicsAcoustics(aerodynamicnoise)AerodynamicsAeroelasticityAeronautics

ComputationalFluidDynamics—CFDFlowfieldmeasurementHemodynamicsHydraulics—thephysicalscienceandtechnologyofthestaticanddynamicbehavioroffluids)HydrologyHydrostatics

＝FluidStaticsHydrodynamics

＝FluidDynamicsElectrohydrodynamicsMagnetohydrodynamicsRheologyQuantumhydrodynamics2023/6/1137Fluidmechanicshasthreestudyapproaches.

Thefirstoneisatheoreticalapproach.Whichanalyzestheprimaryandlesserfactorofthequestion,abstractstheoreticalmodel(suchascontinuousmedium,idealfluid,incompressiblefluid,etc),usesmathematicaltoolstofindthegeneralansweraboutthefluidmovement.StudyApproachesofFluidMechanics(1)Introductionbasichypotheses

mathematicalmodelanalyticalsolutiongeneralanswermathematicaltools:

calculus,fieldtheoryexactsolutiontheoreticalanalysis2023/6/1138StudyApproachesofFluidMechanics(2)Thesecondisanexperimentalapproach.Whichsummarizesthefluidquestionbyexperimentasasimilarexperimentmodel,observesthephenomenaanddeterminesthedataandconjecturestheexperimentresultsaccordingtoacertainmethod.experimentalstudymodelexperimentsobservation&measurementconverttoprototypesimilaritytheoryexperimentaldatasimilarmodel2023/6/1139MarvellousphenomenaofflowFluidflowpastacylinder

—Cat'seyephenomenon——RenumberFluidflowpastasphericalbody——boundarylayerseparationwakezoneincomingflow2023/6/1140StudyApproachesofFluidMechanics(3)Thethirdisacalculatingapproach.Whichdrawsouttheexperimentschemeaccordingtothetheoryanalysisandexperimentobservation,inputsthedatabyprogramandcalculatesthenumericalsolutionwithcomputer.numericalcalculationmathematicalmodelnumericalmodelnumericalsolutiondiscretizedequationsgoverningequationsapproximatesolutionBoundaryconditions&initialconditionscomputer2023/6/1141KarmanvortexstreetduetoairflowspastacylinderCFDVortexsheddingbehindacircularcylinder.Inthisanimation,theflowonthetwosidesofthecylinderareshownindifferentcolors,whichshowsthatthevorticesareformedfromthetwosidesalternately.2023/6/1142SimulationofKarmanvortexCFDFluidflowspasta2Dbody2023/6/1143Velocity&pressuredistributionsintheflowpassageofacentrifugalfanCentrifugalfanCFD2023/6/1144NumericalsimulationwithCFDPumpCFDmodelpressurevelocity2023/6/1145Air-solidcouplingfluidstructureinteraction,FSICFDDisplacementTotaldeformationStressEquivalentstress2023/6/1146

Thethreeapproacheshaveadvantagesanddisadvantages.Onlysupplementeachothercantheyadvancethedevelopmentoffluidmechanics.Modernfluidmechanicshasbandthethreeapproachestogetherorganicallyandpromotethedevelopmentoffluidmechanicsquickly.StudyApproachesofFluidMechanics(4)2023/6/1147Advantages

Disadvantages

TheoreticalanalysisExact(analytical)solutioncanbeobtained.Flowmechanismcanbe

revealed.Limitedtobasicassumptions.Analyticalsolutionscanbeobtainedonlyinafewcases.Experimentalstudy

ModelexperimentFlowparameterscanbemeasureddirectly.Empiricalrelationscanbefound.Highcost.Highmeasurementtechniqueisrequired.Uneasytochangetheconditions.Affectedbyscaleeffects.NumericalcalculationCanexpandtherangeoftheoreticalsolution.Lowcost.Easytochangeconditions.It’snotaffectedbyscaleeffects.Limitedtotheoreticalmodelandnumericalmodel.Computationalerrorisexist.2023/6/1148EXITImportance(position)ofthecourseMathematics,Mechanics

FundamentalcoursesFluidMechanics

Basicspecialtycourse

SubjectofMechanicalEngng

RelativeprofessionalcoursesIntroductionbridge2023/6/1149ThefirstcontributiontothecomeintobeingofthesubjectoffluidmechanicswasdidbyArchimedesofancientGreece.Hefoundedtheliquidbalancetheoryincludethephysicalprincipleofbuoyancyandbuoyancystability.Heestablishedthebasisofthehydrostatics.Theformationanddevelopmentoffluidmechanicsisfellintofivephases.HistoryofFluidMechanics(1)Introduction

Questionsofprojectile’smovementinfluidwasputforward.Thefirstperiod：beforethe20thce