《直升机空气动力学与飞行原理》课件-模块五：旋翼挥舞（双语）

模块五：旋翼挥舞Rotorwaving直升机空气动力学与飞行原理Helicopteraerodynamicsandprinciplesofflight工作场景旋翼是直升机的升力面，产生使直升机升空的升力；又是直升机的操纵面，提供使直升机升降、俯仰和滚转的操纵力和力矩；而且还是直升机的推进器，拉动直升机向任何方向飞行。Therotoristheliftsurfaceofthehelicopter,whichproducestheliftforcethatliftsthehelicopterintotheair;Itisalsothecontrolsurfaceofthehelicopter,whichprovidesthecontrolforceandtorquethatmakethehelicopterlift,pitchandroll;Anditisalsothethrusterofthehelicopter,pullingthehelicoptertoflyinanydirection.工作场景旋翼的挥舞运动对直升机的稳定性和操纵性起着关键作用，是直升机稳定性和操纵性分析的主要技术特点和难点，也是区别于固定翼飞机稳定性和操纵性的主要根源，因而在分析直升机的平衡和运动之前，应先了解旋翼结构和旋翼的挥舞运动。Theswingingmotionoftherotorplaysakeyroleinthestabilityandmaneuverabilityofthehelicopter,whichisthemaintechnicalcharacteristicsanddifficultiesofthestabilityandmaneuverabilityanalysisofthehelicopter,andisalsothemainsourceofthestabilityandmaneuverabilityofthefixed-wingaircraft.了解旋翼的铰接形式Learnaboutthearticulationoftherotors01Teachingobjective教学目标熟悉桨叶的挥舞运动Familiarizeyourselfwiththemovementofthepaddleswing02理解旋翼的挥舞特性Understandtheswingingcharacteristicsoftherotor03了解直升机的振动与噪声Learnabouthelicoptervibrationandnoise04模块五：旋翼挥舞Rotorwaving任务一：旋翼的铰接形式Articulatedformofrotors直升机空气动力学与飞行原理Helicopteraerodynamicsandprinciplesofflight活动1：旋翼的形式有哪些？01.PARTONEWhataretheformsofrotors?活动1：旋翼的形式有哪些？旋翼的形式由桨毂形式决定，旋翼桨毂根据它的结构设计，主要分为全铰式旋翼桨毂、半刚性跷跷板式旋翼桨毂和刚性旋翼桨毂3类。旋翼形式大致分为全铰式、半铰式、无铰式和无轴承式4种。Theformoftherotorisdeterminedbytheformofthepropellerhub,whichismainlydividedintothreecategories:fullyhingedrotorhub,semi-rigidseesawrotorhubandrigidrotorhubaccordingtoitsstructuraldesign.Therearefourtypesofrotors:fullyhinged,semi-hinged,unhingedandbearingless.全铰式旋翼桨毂包含有轴向铰、垂直铰和水平铰。Afullyarticulatedrotorhubconsistsofaxial,vertical,andhorizontalhinges.活动1：旋翼的形式有哪些？全铰式旋翼Fullyarticulatedrotor半刚性跷跷板式特点：没有摆振铰，结构简单，两片桨叶相连共用一个挥舞铰。Semi-rigidseesawtypeFeatures:Thereisnooscillatinghinge,thestructureissimple,andthetwopaddlesareconnectedtoshareaswinginghinge.活动1：旋翼的形式有哪些？半铰式旋翼Semi-articulatedrotor半刚性跷跷板式和万向接头式都属于半铰式旋翼。Boththesemi-rigidseesawtypeandtheuniversaljointtypebelongtothesemi-articulatedrotor.万向接头式特点：两片桨叶通过各自的轴向铰和桨毂壳体相连接，而桨毂壳体又通过万向接头与旋翼轴相连。UniversaljointtypeFeatures:Thetwobladesareconnectedbytheirrespectiveaxialhingesandthehubhousing,whichinturnisconnectedtotherotorshaftbyauniversaljoint.活动1：旋翼的形式有哪些？半铰式旋翼Semi-articulatedrotor无铰式旋翼没有挥舞铰和摆振铰，只有变距铰。其挥舞和摆振方向都是固定的，桨叶刚性连接到桨毂上，挥舞和摆振运动依靠桨根的弹性变形来实现，仍设有变距铰。Theunhingedrotorhasnoswinghingesandoscillatinghinges,onlyvariablepitchhinges.Thedirectionofswingandoscillationisfixed,thebladesarerigidlyconnectedtothehub,andtheswingandoscillationmovementsrelyontheelasticdeformationofthepropellerroot,andthereisstillavariablepitchhinge.活动1：旋翼的形式有哪些？无铰式旋翼Unhingedrotors无轴承式旋翼又称为刚性旋翼，取消了轴向铰、水平铰和垂直铰，除了周期变距，这种桨毂不提供旋翼任何的活动。桨叶的挥舞、摆振和变距运动都是由桨叶根部的柔性元件来完成。活动1：旋翼的形式有哪些？无轴承式旋翼Bearinglessrotorasrigidrotors,eliminateaxial,horizontalandverticalhinges,anddonotprovideanymovementoftherotorexceptforperiodicpitchchanges.Theswinging,oscillatingandvariablepitchmovementsofthepropellersarealldonebyflexibleelementsattherootofthepropellers.活动2：旋翼上的铰链发挥什么作用？02.PARTONEWhatroledothehingesontherotorplay?活动2：旋翼上的铰链发挥什么作用？直升机随着飞行状态的变化和飞行员的操纵，旋翼桨叶发生挥舞运动、桨距改变和摆振运动。Withthechangeofflightstatusandthepilot'smanipulation,therotorbladesundergoswingingmotion,pitchchangeandoscillatingmotion.活动2：旋翼上的铰链发挥什么作用？桨叶自由挥舞和摆振运动的目的就是在旋转运动中寻找平衡。铰链的作用就是让每片桨叶独立地作挥舞和摆振运动。Thepurposeofthefreeswingingandoscillatingmotionofthepaddleistofindbalanceintherotationalmotion.Thefunctionofthehingeistoalloweachpaddletoswingandoscillateindependently.活动2：旋翼上的铰链发挥什么作用？轴向铰（变距铰）——改变旋翼的桨距，从而改变旋翼桨叶的升力。垂直铰（摆振铰）——消除旋转过程中科氏力矩对桨叶的影响。水平铰（挥舞铰）——使桨叶绕挥舞铰产生的力矩无法传递到机身上，从而消除横侧不平衡力矩。AxialHinge(VariablePitchHinge)-Changesthepitchoftherotorblades,thuschangingtheliftoftherotorblades.Verticalhinge(swinghinge)-eliminatestheeffectoftheKochmomentonthepaddleduringrotation.Horizontalhinge(swinghinge)-eliminatesthetransverseunbalancemomentbymakingitimpossibleforthemomentgeneratedbythepaddlesaroundtheswinghingetobetransmittedtothefuselage.活动2：旋翼上的铰链发挥什么作用？旋翼桨叶分为无铰外伸量和有铰外伸量两种形式。无铰链外伸量旋翼的可操纵性会变差（受到重心位置的限制）；为了降低重心位置的限制，提高操纵性、加快操纵响应，将旋翼铰链设计成带有铰外伸量。Rotorbladesaredividedintotwoforms:unhingedoverhangoutandhingedoverhang.Maneuverabilityofarotorwithouthingeoutreachbecomesworse(limitedbythecenterofgravityposition);inordertoreducethelimitationsofthecenterofgravityposition,improvemaneuverability,andspeedupthemaneuveringresponse,therotorhingesaredesignedwithhingeoutreach.Summary总结01旋翼的形式有哪些？Whataretheformsofrotors?任务一：旋翼的铰接形式Articulatedformofrotors02旋翼上的铰链发挥什么作用？Whatroledothehingesontherotorplay?课后利用飞机模型，理解并感受旋翼挥舞的魅力吧！模块五：旋翼挥舞Rotorwaving任务二：桨叶挥舞运动Paddlewavingmotion直升机空气动力学与飞行原理Helicopteraerodynamicsandprinciplesofflight活动1：什么是旋翼桨叶的挥舞运动？01.PARTONEWhatistheswingingmotionofarotorblade?旋翼运动特点：旋翼桨叶一边旋转一边随着直升机机体一起运动，是两种运动的合成。

Rotormotioncharacteristics:Therotorbladesrotateandmovewiththehelicopterbody,whichisasynthesisoftwomovements.活动1：什么是旋翼桨叶的挥舞运动？桨叶挥舞的目的：化解不对称气流对旋翼拉力的影响，避免直升机倾覆；也使空气动力合力向前、后、左、右倾斜，从而得到在水平面内任何方向的分力。Thepurposeofthebladeswingistoresolvetheinfluenceoftheasymmetrical活动1：什么是旋翼桨叶的挥舞运动？airflowonthetensionoftherotorandavoidthehelicopterfromcapsizing,andalsototilttheaerodynamicforceforward,backward,leftandright,soastoobtainthecomponentforceinanydirectioninthehorizontalplane.活动1：什么是旋翼桨叶的挥舞运动？桨叶挥舞运动包括Paddlewavingsportsinclude自然挥舞操纵挥舞随动挥舞SwingnaturallyManipulativeswingingSwingwithyourmove活动2：桨叶是如何挥舞的呢？02.PARTONEHowdoyouswingthepaddles?活动2：桨叶是如何挥舞的呢？自然挥舞Swingnaturally操纵方法：直接控制——没有挥舞铰间接控制——安装挥舞铰Manipulationmethod:Directcontrol–noswinginghingesIndirectcontrol–installationofwavinghinges定义：把非操纵因素引起的桨叶挥舞运动称为桨叶的自然挥舞。Definition:Themovementofthepaddlewavecausedbynon-manipulativefactorsiscalledthenaturalwavingofthepaddle.活动2：桨叶是如何挥舞的呢？自然挥舞Swingnaturally由于旋翼的挥舞促使桨叶绕挥舞铰产生的力矩就无法传递到机身上，从而消除了横侧不平衡力矩。Sincetheswingoftherotorcausesthebladestoswingaroundthehinge,thetorquegeneratedbytheswinghingecannotbetransmittedtothefuselage,thuseliminatingthetransverseunbalancedmoment.挥舞运动包括上挥和下挥。Swingmovementsincludeanupwardanddownwardswing.活动2：桨叶是如何挥舞的呢？自然挥舞Swingnaturally为了避免桨叶向上或向下挥舞角超过规定值，一般通过弹簧机构或旋转离心力防止桨叶下垂过大。所以，直升机旋翼上一般会安装挥舞限动器和下垂限动器。Inordertopreventthepropellerswingingangleupwardsordownwardsfromexceedingthespecifiedvalue,thepropellerisgenerallypreventedfromsaggingtoomuchbyspringmechanismorrotatingcentrifugalforce.Therefore,helicopterrotorsaregenerallyequippedwithwavelimitersandsaglimiters.活动2：桨叶是如何挥舞的呢？桨叶的摆振Oscillationofthepaddles当直升机前飞时，桨叶绕挥舞铰上下挥舞，会使桨叶旋转角速度发生变化。Whenthehelicopterfliesforward,thepropellersswingupanddownaroundtheswinginghinge,whichwillchangetheangularvelocityofthepropellers.活动2：桨叶是如何挥舞的呢？桨叶的摆振Oscillationofthepaddles桨叶向上挥舞时，桨叶旋转角速度增大，桨叶加速旋转；桨叶向下挥舞时，桨叶旋转角速度减小，桨叶减速旋转。Whenthepropellerswingsupward,theangularvelocityofthepropellerrotationincreases,andthepropelleracceleratesandrotates;Whenthepropellerswingsdownward,theangularvelocityofthepropellerrotationdecreases,andthepropellerslowsdownandrotates.活动2：桨叶是如何挥舞的呢？桨叶的摆振Oscillationofthepaddles桨叶加速或减速旋转时，受到的科氏力大小和方向周期变化，对桨叶的强度不利；桨叶旋转时也会产生惯性离心力，结构有可能疲劳受损。为解决这两个问题就在桨毂上安装摆振铰（垂直铰）。Whenthepropelleracceleratesordeceleratesandrotates,theCoriolisforceanddirectionperiodchangesarenotconducivetothestrengthofthepropeller.Inertialcentrifugalforceisalsogeneratedwhenthepaddlerotates,andthestructuremaybefatiguedanddamaged.Inordertosolvethesetwoproblems,apendulumhinge(verticalhinge)isinstalledonthepaddlehub.活动2：桨叶是如何挥舞的呢？桨叶的摆振Oscillationofthepaddles经过桨叶受力状态的分析可知，桨叶绕摆振铰的摆振角分别与桨叶质量和转速成反比，转速越大，摆振角越小；桨叶质量越大，摆振角越小。Throughtheanalysisofthestressstateofthepropeller,itcanbeseenthattheoscillationangleofthepropelleraroundtheoscillatinghingeisinverselyproportionaltothepropellermassandrotationalspeed,andthelargerthespeed,thesmallertheoscillationangle.Thegreaterthemassofthepropeller,thesmallertheoscillationangle.活动2：桨叶是如何挥舞的呢？桨叶的摆振Oscillationofthepaddles如果在垂直铰上安装限动块，桨叶摆振受到限制，即摆振限动，桨叶摆动最大角度受到限动块的限制。Ifalimitingblockisinstalledontheverticalhinge,thepropelleroscillationislimited,thatis,theoscillationislimited,andthemaximumangleofthepropelleroscillationislimitedbythelimitingblock.活动2：桨叶是如何挥舞的呢？桨叶的变距Pitchchangeofthepropeller桨叶绕轴向铰转动来改变安装角或桨叶角，称为桨叶变距。Thepropellerrotatesaroundtheaxialhingetochangethemountingangleorbladeangle,whichiscalledthepropellerpitch.活动2：桨叶是如何挥舞的呢？桨叶的变距Pitchchangeofthepropeller自动倾斜器是直升机改变旋翼倾斜方向和桨叶倾角的专用装置。周期变距操纵杆连接到自动倾斜器再连接到旋翼桨叶，通过操纵变距杆，桨叶就会绕着变距铰转动，从而实现桨距改变。Theautomatictilterisaspecialdeviceforthehelicoptertochangethedirectionofinclinationoftherotorandtheinclinationoftheblades.Thecyclicpitchleverisconnectedtoanautomatictilterandthentotherotorblades,whichrotatearoundthepitchhingebymanipulatingthepitchlever.活动2：桨叶是如何挥舞的呢？操纵挥舞Manipulativeswinging定义：由周期变距引起旋翼的挥舞作用称之为操纵挥舞。Definition:Theswingingeffectoftherotorcausedbytheperiodicpitchchangeiscalledmanipulativeswing.周期变距杆操纵旋翼时，变距拉杆上下运动引起旋翼斜盘倾斜，桨叶旋转时其桨叶角就会周期性发生改变。Whentheperiodicpitchlevercontrolstherotor,theupanddownmovementofthepitchlevercausestherotorswashplatetotilt,andthebladeanglewillperiodicallychangewhenthebladerotates.活动2：桨叶是如何挥舞的呢？操纵挥舞Manipulativeswinging由于斜盘的倾斜引起的桨叶角变化，在9点钟位置桨叶角最大，在3点钟位置桨叶角最小。Thechangeinthebladeangleduetothetiltoftheswashplateisthelargestat9o'clockandthesmallestat3o'clock.活动2：桨叶是如何挥舞的呢？随动挥舞Swingwithyourmove定义：随直升机运动而发生的旋翼挥舞称为随动挥舞。Definition:Therotorswingthatoccurswiththemotionofthehelicopteriscalledfollowerswing.直升机作曲线机动飞行时；直升机的俯仰或滚转等角运动终止时。Whenthehelicopterisflyinginacurvedmaneuver;Whenthepitchorrollisometricmovementofthehelicopteristerminated.Summary总结01什么是旋翼桨叶的挥舞运动？Whatistheswingingmotionofarotorblade?任务二：桨叶挥舞运动Paddlewavingmovement课后玩一玩竹蜻蜓，结合上课内容，深入理解桨叶的挥舞运动。02桨叶是如何挥舞的呢？Howdoyouswingthepaddles?模块五：旋翼挥舞Rotorwaving任务三：旋翼挥舞特性RotorWaveCharacteristics直升机空气动力学与飞行原理Helicopteraerodynamicsandprinciplesofflight活动1：什么是方位角？01.PARTONEWhatisazimuth？活动1：什么是方位角？直升机在悬停时，旋翼流场轴对称，所以每片桨叶受到的气动力也是相同的，与桨叶方位无关。Whenthehelicopterishovering,therotorflowfieldaxisissymmetric,sotheaerodynamicforceoneachpaddleisalsothesame,independentofthepaddleorientation.在前飞状态下，旋翼流场轴不对称，出现旋翼周向相对气流不对称现象，桨盘产生的气动力与各桨叶方位有关。Whileintheforwardflightstate,therotorflowfieldaxisisasymmetric,thephenomenonofrotorcircumferentialrelativeairflowasymmetryoccurs,andtheaerodynamicforcegeneratedbythepaddlediskisrelatedtotheorientationofeachpaddle.活动1：什么是方位角？沿着旋翼旋转方向按递增方式确定方位角，正后方0°方位表示为方位角ψ=0°,或表示为ψ=360°,正右方的方位角为ψ=90°,正前方的方位角为ψ=180°,正左方的方位角为ψ=270°。Determinetheazimuthinanincrementalmanneralongthedirectionofrotationoftherotor.0°azimuthatthebackisexpressedasazimuthψ=0°,orasψ=360°,azimuthattherightisψ=90°,azimuthatthefrontisψ=180°,andazimuthattheleftisψ=270°.活动1：什么是方位角？活动2：什么是相位滞后现象？02.PARTONEWhatisthephaselagphenomenon?活动2：什么是相位滞后现象？当一个外力沿轴线方向作用在转动中的陀螺上，则陀螺的旋转平面将倾斜，倾斜的最大位移量发生在沿陀螺转动方向90°滞后的点上。这是陀螺进动性原理。Whenanexternalforceisappliedtoarotatinggyroscopeintheaxialdirection,theplaneofrotationofthegyroscopewillbetilted,andthemaximumdisplacementofthetiltoccursatthepointwherethegyroscoperotateswitha90°lag.Thisistheprincipleofgyroscopicmotion.活动2：什么是相位滞后现象？挥舞角最大(最小)对应的方位角比挥舞角速度最大(最小)对应的方位角恰好滞后90°。Theazimuthanglecorrespondingtothemaximum(minimum)swingangleisexactly90°behindtheazimuthanglecorrespondingtothemaximum(minimum)swinganglespeed.活动3：桨叶各剖面气流有什么特点？03.PARTONEWhatarethecharacteristicsoftheairflowineachprofileofthepaddle?活动3：桨叶各剖面气流有什么特点？由桨叶后缘流向前缘的气流叫返流，或反流。桨叶上存在返流的区域称为返流区，或反流区。Airflowfromthetrailingedgeofthepaddletotheleadingedgeiscalledbackflow,orcounterflow.Theareaofthepaddlewherethereturnflowexistsiscalledthereturnzone,orbackflowzone.活动3：桨叶各剖面气流有什么特点？返流区的大小与飞行速度和旋翼转速有关。前进比越小，返流区越小；前进比越大，返流区越大。Thesizeofthereturnareaisrelatedtotheflightspeedandrotorspeed.Thesmallertheforwardratio,thesmallerthereturnarea;thelargertheforwardratio,thelargerthereturnarea.活动3：桨叶各剖面气流有什么特点？直升机在前飞、后退飞行或侧飞中，旋翼桨叶的周向相对气流会出现不对称现象。旋翼桨叶的周向相对气流不对称的现象，叫作相对气流不对称性。Helicoptersexperienceasymmetryinthecircumferentialdirectionoftherotorbladesrelativetotheairflowinforwardflight,backwardflight,orsidewaysflight.Thephenomenonofcircumferentialrelativeairflowasymmetryofarotorbladeiscalledrelativeairflowasymmetry.活动3：桨叶各剖面气流有什么特点？前进比越大，旋翼相对气流的不对称性越大；前进比越小，旋翼相对气流的不对称性越小。Thegreatertheforwardratio,thegreatertheasymmetryoftherotorrelativetotheairflow;thesmallertheforwardratio,thelesstheasymmetryoftherotorrelativetotheairflow.活动3：桨叶各剖面气流有什么特点？由于旋翼相对气流的不对称性和返流区的存在，造成的旋翼两侧拉力不对称现象，就形成了横侧不平衡力矩。Thephenomenonofasymmetrictensiononbothsidesoftherotorcausedbytheasymmetryoftherotorrelativetotheairflowandthepresenceofthereturnzonecreatesatransverseunbalancemoment.活动3：桨叶各剖面气流有什么特点？在桨叶相对气流不对称性的影响下，因挥舞速度不同所引起的桨叶迎角不对称性。前行桨叶区内的迎角小，而后行桨叶区内的迎角大。Asymmetryinthepaddleheaderanglecausedbydifferentwavingspeedsundertheinfluenceofthepaddlerelativeairflowasymmetry.Theangleofapproachwithintheforwardpaddleareaissmall,whiletheangleofapproachwithinthebackwardpaddleareaislarge.活动4：旋翼自然挥舞有什么特性？04.PARTONEWhatarethepropertiesofanaturalswingofarotor?活动4：旋翼自然挥舞有什么特性？Therotorconeisbackedup:Whenthehelicopterisinforwardflight,therotorbladetensionoftherotatingrotorbladevariesinasinusoidalpattern.Themaximumbladeupswingspeedandthehighestswingposition(maximumupswingdistance)arenotinthesameorientation;theydifferby90°azimuth.旋翼锥体后倒：当直升机在前飞时，旋转旋翼的桨叶拉力按正弦规律变化。桨叶上挥速度最大和挥舞最高位置(上挥距离最大)不在同一方位，它们之间相差90°方位角。活动4：旋翼自然挥舞有什么特性？由于桨叶的周向气流速度不对称引起的自然挥舞运动，相对于桨毂旋转平面，轨迹前高后低，旋翼呈现为倒锥体向后倾斜，旋翼产生后倒姿态。Duetothenaturalwavingmotioncausedbytheasymmetricairflowvelocityinthecircumferentialdirectionofthepaddles,thetrajectoryishighinthefrontandlowinthebackwithrespecttotherotationalplaneofthepaddlehub,andtherotorispresentedasaninvertedconetiltedbackward,andtherotorproducesabackwardinvertedattitude.活动4：旋翼自然挥舞有什么特性？旋翼锥体侧倾：由于旋翼锥度角的存在，经过旋翼前半部分区域的桨叶会产生额外的上冲气流；经过旋翼后半部分区域的桨叶会产生额外的下沉气流。Therotorconeistiltedsideways:Asaresultoftherotortaperangle,paddlespassingthroughthefronthalfoftherotorareacreateadditionalupwashairflow;paddlespassingthroughthebackhalfoftherotorareacreateadditionaldownwashairflow.活动4：旋翼自然挥舞有什么特性？根据陀螺进动性原则，旋翼锥体向90°方位倾斜，旋翼产生侧倾姿态。右旋旋翼则锥体右倾，左旋旋翼则左倾。Accordingtotheprincipleofgyro-incidence,therotorconeistiltedina90°orientation,andtherotorproducesasideways-tiltedattitude.Aright-handedrotortiltstheconetotheright,whilealeft-handedrotortiltsittotheleft.Summary总结01什么是方位角？Whatisazimuth？任务二：旋翼的挥舞特性RotorWaveCharacteristics02什么是相位滞后现象？Whatisthephaselagphenomenon?课后玩一玩地陀螺，感受一下陀螺的进动性和稳定性03桨叶各剖面气流有什么特点？Whatarethecharacteristicsoftheairflowineachprofileofthepaddle?04旋翼自然挥舞有什么特性？Whatarethepropertiesofanaturalswingofarotor?模块五：旋翼挥舞Rotorwaving任务四：直升机振动与噪声Helicoptervibrationandnoise直升机空气动力学与飞行原理Helicopteraerodynamicsandprinciplesofflight工作场景由于直升机是一个复杂的动力系统，其转动部件很多。只要发动机和旋翼在工作，不管在空中还是地面，都不可避免地存在振动，产生噪声。Sincethehelicopterisacomplexpowersystem,ithasmanyrotatingparts.Aslongastheengineandrotorbladesareinoperation,whetherintheairorontheground,vibrationisinevitableandnoiseisgenerated.工作场景随着军用直升机对隐身要求的提高和适航条例对民用直升机噪声的严格限制，旋翼噪声机理及其降噪技术已经成为直升机技术研究的热点之一。直升机飞行员和维修人员都必须掌握直升机振动和噪声的类型，了解引起共振的原因。Withtheimprovementofmilitaryhelicopters'stealthrequirementsandthestrictlimitationofcivilhelicopternoisebyairworthinessregulations,therotornoisemechanismanditsnoisereductiontechnologyhavebecomeoneofthehotspotsofhelicoptertechnologyresearch.Helicopterpilotsandmaintenancepersonnelmustmasterthetypesofhelicoptervibrationandnoiseandunderstandthecausesofresonance.活动1：直升机的振动可以分为哪几类？01.PARTONEVibrationsfromhelicopterscanbeclassifiedintowhichcategories?活动1：直升机的振动可以分为哪几类？振源就是作用于结构、系统的激振力的来源。直升机的振源主要有旋翼、尾桨和发动机等旋转部件。Thesourceofvibrationisthesourceoftheexcitationforceactingonthestructureorsystem.Themainsourcesofvibrationinhelicoptersarerotatingpartssuchasrotorblades,tailrotorandengines.振动频率指单位时间内振动发生的次数，是识别振动来源的一个主要指标，单位为赫兹(Hz)。根据振源的振动频率，直升机振动分为低频振动、中频振动和高频振动。Vibrationfrequencyreferstothenumberoftimesavibrationoccursperunitoftime,andisaprimaryindicatorforidentifyingthesourceofthevibration,measuredinhertz(Hz).Accordingtothevibrationfrequencyofthevibrationsource,helicoptervibrationisdividedintolow-frequencyvibration,medium-frequencyvibrationandhigh-frequencyvibration.活动1：直升机的振动可以分为哪几类？活动2：直升机的噪声主要包括哪些？02.PARTONEWhatarethemaincomponentsofhelicopternoise?直升机的振动通过结构自振源传至座舱，同时，当这些噪声作用在座舱壁板上时，形成壁板结构振动，进而产生结构性噪声，形成具有周期振动的性质。Thevibrationofthehelicopteristransmittedtothecockpitthroughthestructuralself-oscillationsource,andatthesametime,whenthesenoisesactonthecockpitwallpanels,itformsthestructuralvibrationofthewallpanels,whichinturngeneratesstructuralnoises,formingthenatureofhavingperiodicvibration.活动2：直升机的噪声主要包括哪些？直升机噪声主要包括：旋翼噪声、尾桨噪声和发动机噪声。直升机旋翼是直升机的主要噪声源。旋翼的噪声起源于旋翼非定常运动而引起其周围流体快速的非定常变化。Helicopternoisemainlyincludes:rotornoise,tailrotornoiseandenginenoise.Helicopterrotoristhemainnoisesourceofhelicopter.Therotornoiseoriginatesfromthenon-constantmotionoftherotorandtherapidnon-constantchangeofthefluidaroundit.活动2：直升机的噪声主要包括哪些？旋翼噪声包括旋转噪声和宽带噪声，又可分为厚度噪声、载荷噪声、BVI噪声等。Rotornoiseincludesrotationalnoiseandbroadbandnoise,whichcanbefurthercategorizedintothicknessnoise,loadnoise,BVInoise,andsoon.活动2：直升机的噪声主要包括哪些？活动3：与飞行状态有关的振动包括什么？03.PARTONEWhatarethevibrationsassociatedwiththestateofflight?活动3：与飞行状态有关的振动包括什么？飞行速度过大时的振动：直升机飞行速度过大，会引起从旋翼传来的激振力和力矩增大，使直升机强烈振动。Vibrationatexcessiveflightspeeds:Excessivehelicopterflightspeedscauseanincreaseintheexcitationforceandmomentfromtherotorblades,causingthehelicoptertovibratestrongly.活动3：与飞行状态有关的振动包括什么？“过渡速度”的振动：直升机在起飞增速和着陆消速阶段，在某一飞行速度范围内，会出现明显的抖动现象，这个出现抖动的飞行速度范围，习惯上称之为“过渡速度”。“Transitionspeed”vibration:Helicoptersinthetakeoffspeedincreas