简介：ItiswellknownthattheReynoldsnumberhasasignificanteffectonthevortex-inducedvibrations(VIV)ofcylinders.Inthispaper,anovelin-line(IL)andcross-flow(CF)couplingVIVpredictionmodelforcircularcylindershasbeenproposed,inwhichtheinfluenceoftheReynoldsnumberwascomprehensivelyconsidered.TheStrouhalnumberlinkedwiththevortexsheddingfrequencywascalculatedthroughafunctionoftheReynoldsnumber.ThecoefficientofthemeandragforcewasfittedasanewpiecewisefunctionoftheReynoldsnumber,anditsamplificationresultedfromtheCFVIVwasalsotakenintoaccount.TheoscillatingdragandliftforcesweremodelledwithclassicalvanderPolwakeoscillatorsandtheirempiricalparametersweredeterminedbasedonthelock-inboundariesandthepeak-amplitudeformulas.Anewpeak-amplitudeformulafortheILVIVwasdevelopedundertheresonanceconditionwithrespecttothemass-dampingratioandtheReynoldsnumber.Whencomparedwiththeresultsfromtheexperimentsandsomeotherpredictionmodels,thepresentmodelcouldgivegoodestimationsonthevibrationamplitudesandfrequenciesoftheVIVbothforelastically-mountedrigidandlongflexiblecylinders.ThepresentmodelconsideringtheinfluenceoftheReynoldsnumbercouldgenerallyprovidebetterresultsthanthatneglectingtheeffectoftheReynoldsnumber.

简介：FlowsaroundacircularcylinderdisplayinganunsteadyvortexsheddingprocessattheReynoldsnumbersof1000,3900and1×104arestudiedusingafinite-volumeTotalVariationDiminishing(TVD)schemeforsolvingtheUnsteadyReynolds-AveragedNavier-Stokes(URANS)equations.AnElementalVelocityVectorTransformation(EVVT)approachisproposedforthelocalnormalandtangentialvelocitytransformationattheinterfacesofmainandsatelliteelements.Thepresentedmethodisvalidatedbycomparingwiththeavailableexperimentaldataandnumericalresults.Itisshownthatthetwo-dimensionalTVDfinitevolumemethodwiththeRenormalizationGroup(RNG)turbulencemodelcanbeusedtodeterminehydrodynamicforcesandcapturesvortexsheddingcharacteristicsverywell.

简介：Themajorcausesofthesoundpressurelevel(SPL)variationduetothechangesoftheinclinedangleofacircularcylinderandtheaspectratio(ratioofdistancebetweenendplatestocylinderdiameter)wereinvestigated.Thevelocityfluctuationofthewakeandthesurfacepressurefluctuationofthecylinderweremeasuredinalownoisewindtunneltofindthecorrelationlength,coherentoutputpowerandStrouhalnumber.TheresultsshowthatthechangesofthesevaluesqualitativelycorrespondwiththechangeofSPL.Flowvisualizationtestsareperformedtoclarifythevariationofwakeinrelationwithinclinedangleandaspectratio.ItisfoundthatthespanwisestructureofKarman’svortexstreetisbrokendownbytheupwardflowsgeneratedaroundthebottomendplate,andthedegreeoftheinterferencebetweentheupwardflowandKarman’svortexstreetissmallerwhentheaspectratioislarger.

简介：Acoaxialinsulated-rod-to-cylinderunderwaterstreamerdischargesystemcapableofinjectingplasmaintoalargevolumeofwaterwasdevelopedandemployedtodecolorizeazodyesunsetyellow.Therodtypeanodewascoveredbyaninsulatortubewithawallthicknessof0.4mm.Aseriesofslitswithawidthof20μmto80μmandalengthofabout4mmwerecutontothewalloftheinsulatortube.Dependingonthesolutionconductivity,acylindricaldischargeregionwithalengthof60mmandawallthicknessof5mmto11mmformsinthereactor.Theinfluenceofthesolutionconductivity,pHandpulsefrequencyonthedecolorationofsunsetyellowwasinvestigated.Theresultsshowthatthesolutionconductivityhaslittleeffect,whilethesolutionpHandthepulsefrequencyhavesignificantinfluenceonthedecolorationrateofsunsetyellow.Thedecolorationrateofsunsetyellowisincreasedwiththeincreaseinpulsefrequency.AlowerpHinsolutionpromotesthedecolorationofsunsetyellowwhileahigherpHinhibitsit.

简介：Inthisstudy,anelectro-mechanicalvalve(EMV)systemfortheintakevalveofafourstroke,singlecylinder,overheadvalveandsparkignition(SI)enginewasdesignedandconstructed.AnenginewiththeEMVsystemandastandardengineweretestedtoobservetheeffectsoftheEMVonengineperformanceandemissionsatdifferentspeedsunderfullload.TheEMVengineshowedimprovedenginepower,enginetorqueandbreakspecificfuelconsumption(BSFC).A66%decreaseinCOemissionswasalsoobtainedwiththeEMVsystem,buthydrocarbons(HC)andNOxemissionsincreasedby12%and13%respectively.

简介：Theproblemofair-fuelratio(AFR)controloftheportinjectionsparkignition(SI)engineisstillofconsiderableimportancebecauseofstringentdemandsonemissioncontrol.Inthispaper,thestaticAFRcalculationmodelbasedonin-cylinderpressuredataandontheadaptiveAFRcontrolstrategyispresented.Themodelutilisestheintakemanifoldpressure,enginespeed,totalheatrelease,andtherapidburnangle,asinputvariablesfortheAFRcomputation.Thecombustionparameters,totalheatrelease,andrapidburnangle,arecalculatedfromin-cylinderpressuredata.ThisproposedAFRmodelcanbeappliedtothevirtuallambdasensorforthefeedbackcontrolsystem.Inpracticalapplications,simpleadaptivecontrol(SAC)isappliedinconjunctionwiththeAFRmodelforport-injectedfuelcontrol.TheexperimentalresultsshowthattheproposedmodelcanestimatetheAFR,andtheaccuracyoftheestimatedvalueisapplicabletothefeedbackcontrolsystem.Additionally,theadaptivecontrollerwiththeAFRmodelcanbeappliedtoregulatetheAFRoftheportinjectionSIengine.

简介：Physicalmodeltestswerecounductedtopredictlocalscourandmaximumscourdeptharoundthelargediametercylinderslocatedinthe(sand)seabedundertheactionofbothwaveandcurrent.Accordingtotheresultoftests,ananalysiswasmadeonallthefactorsinfluencingthescour.Theresultsshowsthatfortheseabedwithrelativefinegrainsinshallowwater(0.07＜h/L≤0.28),whentherelativediameterD/Lofthecylinderiswithin0.3-0.7,themaineffectivescourfactorsaroundthecylinderintheseabedarediameterDofthecylinder,thewaveheightH,thewavelengthL,thevelocityVcofthecurrentandtheparametersrelatedtotheseabedsoiltexture.Themainparametersinfluecingthemaximumscourdepthwereanalyzed,andthetestdataweresyntherized,toobtaintheformulapredictingthescourdeptharoundthelargediametercylinderundertheofbothwaveandcurrent.

简介：Inthispaper,aniterationmethodispresentedtocalculatethesteadynoseparationflowpastacircularcylinderwithbrokenline-shapedvelocityprofile.Ateachiterationstep,thestreamlinesofthelaststepareconsideredasequivorticitylinestodeterminethenewflowfield.Theiterativeprocessisstoppedwhencertainconvergencecriterionisreached.Severalexamplesaregivenwhichshowtheeffectivenessofthemethod.

简介：现在的学习在拉长的柱体上面对magnetohydrodynamics和热产生/吸收系数在威廉森液体的停滞点流动上揭示homogeneous/hetereogeneous反应的效果。进一步，可变热电导率和热层化的效果也被考虑。管理部分微分方程在类似转变的帮助下被变换成平常的微分方程。系统联合了非线性的平常的微分方程然后被射击解决技术。MATLAB射击代码被比较在限制情况与以前出版的工作验证。当现在的结果与MATLAB内建的功能bvp4c相比时，结果进一步被加强。突出的参数的效果为速度，温度和集中侧面图形地被商讨。为不同参数的皮磨擦系数和Nusselt数字在桌子的帮助下被调查。

简介：Anexperimentalstudyonabareflexiblecylinderaswellascylindersfittedwithtwotypesofcross-sectionedhelicalstrakeswascarriedoutinatowingtank.Themainpurposeofthispaperistoinvestigatetheeffectsofstrakes'crosssectiononthevortex-inducedvibrations(VIV)suppressionofaflexiblecylinder.Thesquare-sectionedandroundsectionedhelicalstrakeswereselectedintheexperimentaltests.Theuniformcurrentwasgeneratedbytowingthecylindermodelsalongthetankusingatowingcarriage.TheReynoldsnumberwasintherangeof800–16000.Thestrainresponsesweremeasuredbythestraingagesincross-flow(CF)andin-line(IL)directions.Amodalanalysismethodwasadoptedtoobtainthedisplacementresponsesusingthestrainsignalsindifferentmeasurementpositions.Thecomparisonoftheexperimentalresultsamongthebarecylinder,square-sectionedstrakedcylinderandroundsectionedstrakedcylinderwasperformed.Thehelicalstrakescaneffectivelyreducethestrainamplitude,displacementamplitude,responsefrequenciesanddominantmodesofaflexiblecylinderexcitedbyVIV.Andthemeandragcoefficientsofstrakedcylinderswereapproximatelyconsistentwitheachother.Inaddition,thesquaresectionedandround-sectionedstrakesnearlysharethesimilarVIVreductionbehaviors.Sometimes,thestrakeswithround-sectionrepresentmoreexcellenteffectsontheVIVsuppressionofresponsefrequencythanthosewithsquaresection.

简介：

简介：在经历8天的联合潮汐的电流，循环和波浪行动以后，搜索包围自由地在1月在华东海(ECS)在沙的海床上休息的柱体目标的深度数字地用设计为的DRAMBUIE模型被预言广泛地搜索埋葬，它是使用并且验证由在原处实验。在数字集成的时期期间，timet的值通常是可变的在每次，经由特殊走时间的途径的步由这份报纸发展了消除时间错误。潮汐的当前的速度，波浪在ECS的轨道的速度和平均深度的发行量被数字模拟与沿海的河口和海洋模型(ECOM)获得了，模仿的波浪Nearshore(天鹅)模型和地区性的海洋建模系统(ROMS)分别地当模特儿。有影响的因素在的控制实验和几个理想化的测试用例搜索深度表明主导的水动力学因素是在在正常天气条件下面的ECS的潮汐的电流，并且本地人上的循环和波浪运动搜索的架的影响能几乎与自台湾东面的菲律宾海流向日本的暖流的高速度的主流流动的自台湾东面的菲律宾海流向日本的暖流区域的一个例外被忽略。这也被显示在沙的沉积，分发将近搜索深度跟随潮汐的水流的模式，当时第二等的影响因素在上搜索深度看起来是在ECS的沙的沉积的谷物尺寸。沉积谷物尺寸上的数字测试进一步证明那么更好的沙容易搜索的更多，和一个增加的趋势为与谷物尺寸的减小搜索深度由于更大的大小的粒子的强加的电阻被显示。三个方面由这篇论文探索了，包括在防卫研究机构矿埋葬环境(DRAMBUIE)模型，的实验方程输入和填入过程的精确性能严重地影响预言搜索包围自由地在ECS在沙的海床上休息的柱体目标的深度。

简介：Inthispaper,theinfluenceofthermalperformanceofcathode-heaterassemblyofTravelingWaveTube(TWT),whichhasdifferentcontactformbetweeninnerheatshieldandsupportingcylinder,isanalyzedusingthesimulationsoftwareANSYS.Withboththermalradiationandheatconductionareconsidered,thetemperatureandheatfluxdistributionofstructureswithdifferentcontactformarecalculated,andalsostartingtimewhichisneededbeforetemperaturecomeintosteadystatus.Theresultofanalysissuggeststhatchangingthecontactformbetweeninnerheatshieldandsupportcylindercaninfluencethethermalperformanceofcathode-heaterassemblyandimproveassembly'stemperaturedistributionandpromoteheater'sheatingefficiency.Theresultofthispaperprovidestheoreticalguidanceinthedesignofcathode-heaterassembly.

简介：3-DevolutionofKarmanvortexfilamentsandvortexfilamentsinbraidregionsintheturbulentwakeofa2-Dcirculaxcylinderisinvestigatednumeri-callybasedoninviscidvortexdynamicsbyanalyzingtheresponseoftheinitially2-Dspanwisevortexfilamentstoperiodicspanwisedisturbanceofvaryingmagnitude,wavelengthandinitialphaseangles.Ourresultsrevealakindof3-Dvortexsysteminthewakewhichconsistsoflargescalehorseshoe-shapedvorticesandsmallscaleλ-shapedvortexfilamentsaswellasvortexloops.Themechanismandthedynamicprocessaboutthegenerationofstreamwisevorticalstructureandthe3-Dcoherentstructurearereported.

简介：柱体的垂直摆动与不同直径比率Dd/Dc和厚度比率td/Dc被3D学习(三维)在这份报纸开发的数字模型，并且通过2D与结果相比获得了(二维)数字模型。高顺序的迎风的计划被使用稳定计算，并且集中被多格子方法加速。2D和3D模拟结果之间的差别的质、量的分析与一个依附底部的磁盘在流动地特征和垂直地震荡的柱体的水动力学系数上揭示3D效果。液体领域上的3D效果主要在三个流旋涡的模式的意义被反映：x相对在2D模拟产生的旋涡在锋利的边附近在流动地上有更大的效果。在沿着轴的取向的片，沿着光线的轴的y比沿着环绕的方向的x，更在速度上显示光线的效果在磁盘的锋利的边附近比环绕的效果读了。旋转相互作用在水平飞机的液体的z在举运动期间是不足道的。基于2D和3D模拟结果，分开增加的集体系数和抑制比率的增加的政体的转弯的点被识别。直径比率Dd/Dc和厚度比率td/Dc详细被讨论。

简介：Adimpleappearsonafreesurfacewhilerotatingacylindertankfilledwithliquid.Thedimplestartstoconcentricallydeepertoadrainportatthebottomcenterofthetank.Overtime,thedimplepenetratesthedrainport,afreesurfaceformsalongandslenderstringshapeinthetank,andaso-calledvortexing(aircore)phenomenonoccurs.Thegenerationofavortexcoredependsonthesizeofthetankanddrainport,andonthepropertiesoftheliquidinthetank.Inthisstudy,theliquidlevelandthetimeatwhichthevortexcoreisinitiallygeneratedarenumericallyinvestigatedusingdifferentvaluesoftankdiameter,drainportdiameter,andinitialtankrotationalspeeds.Insteadofafullthree-dimensionalanalysis,atwo-dimensionalaxisymmetricsimulationisconducted.Themomentumconservationequationinthecircumferentialdirectionisadditionallysolvedinthetwo-dimensionalmeshsystem.Severalnon-dimensionalvariablesarecreated:theratiooftheaircoregenerationdistanceandtankdiameter,thediameterratioofthetankanddrainport,therotationalReynoldsnumber,therotationalFroudenumber,andtherotationalWebernumber.Finally,thenon-dimensionalaircoregenerationdistanceiscorrelatedwiththeothernon-dimensionalparameters.

简介：摘 要：文章针对高线分离爪气缸在使用过程中存在的故障进行分析，对影响分离爪气缸缸故障的问题进行改进。

简介：Thepurposeofthispaperistofindsomebettermethodsforcalculatingin-lineforcesonaverticalcircularcylinderandforanalysingthehydrodynamiccoefficientsC_DandC_Minwave-currentco-existingfield.Inthispa-per,inordertocalculatehydrodynamicforces,theauthorstrytofindawayofapplyingagreatnumberofthere-sultsaboutC_DandC_Mforwave-onlyfieldinthecaseofwave-currentco-existingfield,andtheresultsaboutC_DandC_Mobtainedinregularwavesintheeaseofirregularwaves.Suchawaymaybeofsignificanceinengineeringandfurtherresearch.