流体力学英文PPT课件

1、2021-11-251Contents Teaching Contents In Classroom Experimental Projects In Teaching LabTotal hours: 54Classroom teaching hours: 48Practice hours: 6第1页/共54页2021-11-252Teaching Contents (1)Part A (Total hours: 36)nA1 Introduction (4 hours)nA2 Fluid statics (6 hours )nA3 Fluid kinematics (6 hours)nA4

2、Fluid dynamics ( 6 hours)nA5 Laminar flow, turbulent flow and energy loss (8 hours)nA6 Pipe flow and calculation of pipeline (4 hours)nA7 Similarity theory and dimensional analysis (2 hours)Fundamental第2页/共54页2021-11-253Part B (Total hours: 8)lB1 Stream functions and potential functions, frictionles

3、s irrotational flow (4 hours )lB2 Boundary layer theory and flow past body (4 hours)Part C (Total hours: 4)uC1 Resaerch progress in Fluid Mechancis (1 hour)uC2 Modern flow measurement technologies (1 hour)uC3 Introduction to numerical simulation of turbulence flow and commercial softwares of CFD (2

4、hours)Teaching Contents (2)Extended contentsFundamental第3页/共54页2021-11-254Part A and Part B are the foundation of Fluid Mechanics, Part C is the extended contents and refer to some practical problems. This course also pays much attention to the prevalence of modern fluid mechanics, for example, the

5、introduction to the theory of turbulence boundary layer and the sketch of computational fluid dynamics (CFD) will help your further applications after your graduation.Teaching Contents (3)第4页/共54页2021-11-255Experimental Projects (1)In-class (Required) (Total hours: 6)nE1 Hydrostatics (1 hour)nE2 Vel

6、ocity measurement with Pitot tube (1 hour)nE3 Flow measurement with Venturi tube (1 hour)nE4 Verification of Bernoulli equation (1 hour)nE5 Reynolds experiment (1 hour)nE6 Measurement of friction loss coefficient for circular pipe flow (1 hour)第5页/共54页2021-11-256Experimental Projects (2) After-class

7、 (Total hours: 6-8)pE1 Liquid viscosity measurement (1 hour) (Optional) pE2 Demonstrating experiment about flow pattern and streamline (1 hour) (Required) pE3 Measurement of local loss coefficient for circular pipe flow (1 hour) (Required) pE4 Demonstrating experiment about Siphon principle (1 hour)

8、 (Required) pE5 Demonstrating experiment about flow around airfoil and cylinder (1 hour) (Required) pE6 Demonstrating experiment about vortex formation (1 hour) (Required) pE7 Self-designing experiments (1 hour) (Optional) 第6页/共54页2021-11-257TextbookFrank M. White. Fluid Mechanics. McGraw Hill Highe

9、r Education, 7th Revised edition, 2010.2第7页/共54页2021-11-258ReferencesuE. John Finnemore, Joseph B. Franzini. Fluid Mechanics with Engineering Applications. M c G r a w - H i l l H i g h e r Education, 10th Revised edition, 2001.10第8页/共54页2021-11-259Referencesu Jin Xiaohong, Li Yuanhui. Fluid Mechani

10、cs (bilingual Teaching). Beijing: China Power Press, 2011.9第9页/共54页2021-11-2510 5% attendance 10% homework 10% required experiments 5% optional experiments 70% final examGrades第10页/共54页2021-11-2511 When you think about it, almost everything on this planet either is a fluid or moves within or near a

11、fluid. Frank M. WhitePreliminary RemarksFluid can be found almost everywhere on the earth !第11页/共54页2021-11-2512Overview of Fluid Mechanics The concept of fluid The primary physical property of fluid Study objects of Fluid Mechanics The nature of the subject of Fluid Mechanics Tasks of Fluid Mechani

12、cs Study approaches of Fluid Mechanics Importance (position) of the course History of Fluid MechanicsThe following aspects will be discussed第12页/共54页2021-11-2513The concept of a fluid A solid can resist a shear stress by a static deformation. A fluid can not resist a shear stress by a static deforma

13、tion. Any shear stress applied to a fluid, no matter how small, will result in motion of that fluid. The fluid moves and deforms continuously as long as the shear is applied. .Introduction第13页/共54页2021-11-2514Is it has afixed volume？Can it form a free surface？Is it easy to be compressed？Fluidgasnono

14、yesliquidyesyesno FluidSolidyesnoThe primary physical property of fluid第14页/共54页2021-11-2515 Fluid mechanics is an important branch of modern mechanics，Its a science that studies fluids balance (Fluid statics), mechanical movement laws (Fluid Kinematics) and the interaction between fluid and the bou

15、ndaries (Fluid Dynamics), which may be either solid surfaces or interfaces with other fluids. It mainly ascertains the distribution of speed and pressure, energy loss and the interaction force and the moment between fluid and boundary.IntroductionStudy Objects of Fluid Mechanics (1)第15页/共54页2021-11-

16、2516Water and air are researched mostly in fluid mechanics. Besides these, fluid also includes vapor as work medium in turbine, lube oil, water which mixing with mud and sand, blood, melting metal and the gas with complicated components coming from burning, plasmas under high temperature condition,

17、etc.Study Objects of Fluid Mechanics (2)l Stationary boundaries：riverbed, pipe wall, building, etc；l Moving boundaries：aircraft, ship, runner, etc.Types of boundary第16页/共54页2021-11-2517 MechanicsResearch object The carrier of mechanical problemsFluid MechanicsFluidLiquidWaterMechanicsThree conservat

18、ion lawsHydraulicsIntroductionLiquid is the main research object; Mainly focus on engineering applications; Suitable for students in Hydraulic Eng., Civil Eng.The nature of the subject of Fluid MechanicsConservation of mass, momentum and energy第17页/共54页2021-11-2518 Fluid mechanics is not only an age

19、-old subject, but also a new fashion subject which can be researched on quite widely fields. There are many questions about fluid mechanics in these departments, such as in aviation, spaceflight, navigation, astronomical weather, physical geography, water conservancy and hydropower, heat energy refr

20、igeration, building construction and environmental protection, petroleum and chemical engineering, transporting air and liquid, combustion and explosion, metallurgy and mining, biology and sea, war industry and nuclear energy, machine building, mechanical engineering, etc.Tasks of Fluid MechanicsInt

21、roductionEngineering fields and disciplines relative to Fluid Mechanics第18页/共54页2021-11-2519Vortex created by the passage of an Vortex created by the passage of an aircraft wing, revealed by coloured smokeaircraft wing, revealed by coloured smokeTurbulence in the tip vortex from an airplane wingEngi

22、neering fields relative to Fluid Mechanics第19页/共54页2021-11-2520aviationspaceflightnavigationRocket launchingfountain第20页/共54页2021-11-2521Axial-flow fan & centrifugal pumpfanpumpimpeller第21页/共54页2021-11-2522Multi-stage axial-flow compressor modelMulti-stage axial-flow compressor modelCompressor第2

23、2页/共54页2021-11-2523Water turbine and electrical generator cut-away viewWater turbine and electrical generator cut-away view Kaplan turbine runner and bladehydropower第23页/共54页2021-11-2524Model plane tested in a wind tunnelModel plane tested in a wind tunnel Car wind tunnel test Air flow past an aerof

24、oilCooling fan 第24页/共54页2021-11-2525The Three Gorges Dam photographed by satellite of the United StatesHydraulicEngineeringwater conservancy projectDujiangyancomprehensive engng第25页/共54页2021-11-2526Typhoon Tornado: A rotating column of air usually accompanied by a funnel-shaped downward extension of

25、 a cumulonimbus cloud and having a vortex several hundred yards in diameter whirling destructively at speeds of up to 500 miles (800 km) per hour. Typhoon Typhoon: A tropical cyclone occurring in the western Pacific or Indian oceans. Tornado第26页/共54页2021-11-2527vortex formed in the rear of a high-sp

26、eed trainboiling mud near a Volcanic craterTornadoTornado第27页/共54页2021-11-2528vortices in atmosphere Hurricane 第28页/共54页2021-11-2529WeatherCFDsupercomputer第29页/共54页2021-11-2530Dew and drop第30页/共54页2021-11-2531Surface tensionsoap bubble water-drop 第31页/共54页2021-11-2532volleyballfootballtennisswimming

27、rowingdiscus throwgolf ballracecar racingjavelintable tennisbadminton第32页/共54页2021-11-2533Golf ball with smooth & rough surface, Which is better？Question 第33页/共54页2021-11-2534 Golf originated in Scotland in the 15th Century. It was thought in the early days that the golf ball with smooth surface

28、 had small flight resistance, so the ball was made in leather. It was found afterwards that an old ball with many scratches on its surface could fly farther than a new ball with smooth surface. This mystery was not to be solved until the boundary layer theory was established by L. Prandtl in the 20t

29、h Century. The present-day golf has a lot of pits on its surface, and the flight distance of a rough surface ball is 5 times farther than a smooth ball when they have the same size and weight.第34页/共54页2021-11-2535wake zonewake zone第35页/共54页2021-11-2536Disciplines Relative to Fluid Disciplines Relati

30、ve to Fluid MechanicsMechanicsAcoustics (aerodynamic noise) Aerodynamics Aeroelasticity Aeronautics Computational Fluid Dynamics CFDFlow field measurementHemodynamics Hydraulics the physical science and technology of the static and dynamic behavior of fluids) Hydrology Hydrostatics Fluid Statics Hyd

31、rodynamics Fluid Dynamics Electrohydrodynamics Magnetohydrodynamics Rheology Quantum hydrodynamics第36页/共54页2021-11-2537Fluid mechanics has three study approaches. The first one is a theoretical approach. Which analyzes the primary and lesser factor of the question, abstracts theoretical model (such

32、as continuous medium, ideal fluid, incompressible fluid, etc), uses mathematical tools to find the general answer about the fluid movement. Study Approaches of Fluid Mechanics (1)Introductionbasic hypotheses mathematical modelanalytical solutiongeneral answercalculus, field theoryexact solutiontheor

33、etical analysis第37页/共54页2021-11-2538Study Approaches of Fluid Mechanics (2)The second is an experimental approach.Which summarizes the fluid question by experiment as a similar experiment model, observes the phenomena and determines the data and conjectures the experiment results according to a cert

34、ain method. experimental studymodel experiments observation & measurement convert to prototype similarity theoryexperimental datasimilar model第38页/共54页2021-11-2539Marvellous phenomena of flowFluid flow past a cylinder Cats eye phenomenonRe numberFluid flow past a spherical bodyboundary layer sep

35、aration wake zoneincoming flow 第39页/共54页2021-11-2540Study Approaches of Fluid Mechanics (3)The third is a calculating approach. Which draws out the experiment scheme according to the theory analysis and experiment observation, inputs the data by program and calculates the numerical solution with com

36、puter. numerical calculationmathematical model numerical model numerical solution discretizedequationsgoverning equationsapproximate solutionBoundary conditions & initial conditions computer第40页/共54页2021-11-2541Karman vortex street due to air flows past a cylinderCFDVortex shedding behind a circ

37、ular cylinder. In this animation, the flow on the two sides of the cylinder are shown in different colors, which shows that the vortices are formed from the two sides alternately. 第41页/共54页2021-11-2542Simulation of Karman vortexCFDFluid flows past a 2D body第42页/共54页2021-11-2543Velocity & pressur

38、e distributions in the flow passage of a centrifugal fanCentrifugal fanCFD第43页/共54页2021-11-2544Numerical simulation with CFDNumerical simulation with CFDPumpCFDmodelpressurevelocity第44页/共54页2021-11-2545Air-solid couplingAir-solid couplingfluid structure interaction, FSICFDDisplacementTotal deformati

39、onStressEquivalent stress第45页/共54页2021-11-2546 The three approaches have advantages and disadvantages. Only supplement each other can they advance the development of fluid mechanics. Modern fluid mechanics has band the three approaches together organically and promote the development of fluid mechan

40、ics quickly.Study Approaches of Fluid Mechanics (4)第46页/共54页2021-11-2547Advantages Disadvantages Theoretical Theoretical analysisanalysisl Exact (analytical) solution can be obtained.l Flow mechanism can be revealed.l Limited to basic assumptions.l Analytical solutions can be obtained only in a few

41、cases.Experimental Experimental studystudyModel Model experimentexperimentl Flow parameters can be measured directly.l Empirical relations can be found.l High cost.l High measurement technique is required.l Uneasy to change the conditions.l Affected by scale effects.Numerical Numerical calculationca

42、lculationl Can expand the range of theoretical solution.l Low cost.l Easy to change conditions.l Its not affected by scale effects.l Limited to theoretical model and numerical model.l Computational error is exist.第47页/共54页2021-11-2548EXITImportance (position) of the course Fundamental courses Basic

43、specialty course Relative professional coursesIntroductionbridge第48页/共54页2021-11-2549The first contribution to the come into being of the subject of fluid mechanics was did by Archimedes of ancient Greece. He founded the liquid balance theory include the physical principle of buoyancy and buoyancy stability. He established the basis of the hydrostatics . The formation and development of fluid mechanics is fell into five phases.History of Fluid Mechanics (1)Introductionl Questions of projectiles movement