简介：Onthehypothesisthattheturbulentflowispracticallynotaffectedincharacterbypulsationoftheflow,theformulaforsoundpressurelevelofpulsedjetnoiseisobtainedin90°directionand1meterawayfromthenozzle.Thesteadyjetnoiseis,then,aspecialcasewhenthepulsatingfrequencyiszero.Theresultsagreewellwithexperiments.

简介：Numericalinvestigationofatransversesonicjetinjectedintoasupersoniccrossflowwascarriedoutusinglarge-eddysimulationforafree-streamMachnumberM=1.6andaReynoldsnumberRe=1.38×10~5basedonthejetdiameter.Effectsofthejet-to-crossflowmomentumratioonvariousfundamentalmechanismsdictatingtheintricateflowphenomena,includingflowstructures,turbulentcharactersandfrequencybehaviors,havebeenstudied.Thecomplexflowstructuresandtherelevantflowfeaturesaredisc...

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简介：Anewroutewasdevelopedforthesynthesisofrenewabledecalinwithcyclopentanonewhichcanbederivedfromlignocellulose.Itwasfoundthat1,2,3,4,5,6,7,8-octahydronaphthalenecouldbeselectivelyproducedbythehydrogenation/dehydration/rearrangementof[1,1-bi(cyclopentylidene)]-2-one(i.e.theselfaldolcondensationproductofcyclopentanone)overadual-bedcatalystsystem.Amongtheinvestigatedcatalysts,theRu/CandAmberlyst-15resinexhibitedthehighestactivitiesforthehydrogenationof[1,1-bi(cyclopentylidene)]-2-oneto[1,1-bi(cyclopentan)]-2-olandthedehydration/rearrangementof[1,1-bi(cyclopentan)]-2-olto1,2,3,4,5,6,7,8-octahydronaphthalene,respectively.UsingRu/CandAmberlyst-15resinasthefirstbedandthesecondbedcatalysts,1,2,3,4,5,6,7,8-octahydronaphthalenewasdirectlyproducedinhighcarbonyield(83.7%)undermildconditions(393K,1MPa).Afterbeinghydrogenated,the1,2,3,4,5,6,7,8-octahydronaphthalenewasconvertedtodecalinwhichcanbeusedasadditivetoimprovethethermalstabilityandvolumetricheatvalueofjetfuel.

简介：Thecharacteristicsofalaminarwalljetsubmittedtodifferentconfigurationshavebeenexperimentallyexploredinordertoobtainabetterknowledgeoftransitionmodifications,Infactdifferentparameterscanaccelerateordelaythetransitionusingasmoothorroughsurface,heatedornot,submittedtovibrationsornot.Inthisstudy,significanteffectscanbenoticed.Ithasbeenpossibletomeasurethebeginningofgrowthratesofdisturbanceamplitudeusingawindtunnelandcomparingtheresultswiththelinearstabilitytheory.

简介：这份报纸涉及一口跳入的液体喷气的三维的数字模拟。在喷气附近形成一个空气洞的短暂过程，捕获这个大塑造toroidal的水泡的一个开始大的空气水泡，和分散进更小的水泡被分析。一个稳定的有限元素方法(女性)基于适应、未组织的格子在平行数字模拟下面被采用并且结合了一个水平集合方法追踪在空气和液体之间的接口。这些模拟证明液体喷气的惯性开始压抑水池的表面，形成包围液体喷气的一个环形的空气洞。随后在液体水池被形成的一个toroidal液体旋涡导致空气洞倒塌，并且接着乘火车空气进从在液体喷气附近的不稳定的环形的空气差距区域的液体水池。

简介：作为无梭的织布机之一，空气喷气织布机用一口空气喷气的粘性和动能搬运一支纱进经纱。这个拣的系统的性能取决于即时inhalation/exhaust的能力，嘴的配置，一个检查阀门的操作特征，等等。在最近的过去，许多研究在从一个嘴出口解除的空气喷气上被报导了，但是为理解流动的研究回答与联系的特征砍在嘴的层和冲击波层相互作用没足够被进行。在这份报纸，计算研究被执行与一个加速试管在空气喷气嘴解释流动领域并且与可得到的以前的试验性的数据验证了。从计算学习获得的结果证明在超声的流动政体，流动领域显著地取决于加速试管的长度。作为嘴压力比率增加，拖也对绳起作用的力量增加。为一个更长的加速试管，全部的压力损失大，由于摩擦损失。

简介：在现在的学习，一个计算液体动力学方法被使用了在下面膨胀的声音的喷气结构上以水库状况调查过度饱和的起始的度的效果，例如马赫磁盘地点和直径，桶冲击波和喷气边界。调查的axisymmetric嘴几何学是有直部分的一张收敛的嘴。作为结果，过压由于冷凝作用产生，这被发现，没有冷凝作用，有过压的产生的流动的特征与那些由于在喷气的冷凝作用不同。

简介：Experimentswerecarriedouttoeliminatethescreechtonegeneratedfromasupersonicjet.Compressedairwaspassedthroughacircularconvergentnozzleprecededbyastraighttubeofsamediameter.Inordertoreducethejetscreechasphericalreflectorwasusedandplacedatthenozzleexit.Theplacementofthesphericalreflectoratthenozzleexitcontrolledthelocationoftheimagesourceaswellasminimizedthesoundpressureatthenozzleexit.Theweaksoundpressuredidnotexcitetheunstabledisturbanceattheexit.Thustheloopofthefeedbackmechanismcouldnotbeaccomplishedandthejetscreechwaseliminated.Thetechniqueofscreechreductionwithaflatplatewasalsoexaminedandcomparedwiththepresentmethod.Agoodandeffectiveperformanceincancelingthescreechcomponentbythenewmethodwasfoundbytheinvestigation.Experimentalresultsindicatethatthenewsystemsuppressesnotonlythescreechtonesbutalsothebroadbandnoisecomponentsandreducestheoverallnoiseofthejetflow.Thesphericalreflectorwasfoundveryeffectiveinreducingoverallsoundpressurelevelintheupstreamregionofthenozziecomparedtoaflatplate.Thepropsedsphericalreflectorcan.accordingly,protecttheupstreamnoisepropagation.

简介：Thevolumeexpansionofthestuff(e.g.tobaccostem)isofgreatimportancetoanincreaseintheproductqualityandadecreaseintheproductioncost.Thispaterputsforwardthebasicconfigurationandtheexpansionmechanismofanewtypeofjetpressurizationevaporationexpansionapparatur.Bythethermodynamiccalculationoftheapparatus,wegivevariationsinsteampressureonvariouscrosssectionsoftheflowsystemfortheapparatus,manufactureasamplemachine,andfinishruntestsofthemachine.Thetestresultsshowthattheapparatusmaymaketherelativeincreaseinfillvalueoftobaccostemhigherthan75%,andmaycausethesteamconsumptionrequiredintheexpansionprocessofeachkilogramstemtoreducedabout40%comparedwithconventionalexpansionapparatus.Additionally,theconfigurationoftheapparatusissimpleandsmall,itscostofmanufactureisverylow,andbothitsoperationandmaintenanceareextremelyconvenient.

简介：TheeffectsofReynoldsnumberonbothlarge-scaleandsmall-scaleturbulencepropertiesareinvestigatedinasquarejetissuingfromasquarepipe.ThedetailedvelocityfieldsweremeasuredatfivedifferentexitReynoldsnumbersof8×103190,thevalueofA=εL/〈u2)3/2inthepresentsquarejetconvergesto0.5,whichisconsistentwiththeobservationindirectnumericalsimulationsofboxturbulence,butlowerthanthatincircularjet,platewakeflows,andgridturbulence.ThediscrepanciesincriticalReynoldsnumberandA=εL/〈u2〉3/2amongdifferentturbulentflowsmostlikelyresultfromtheflowtypeandinitialconditions.

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简介：Controlofshockwaveandboundarylayerinteractioncontinuestoattractalotofattention.Inrecentdecadesseveralmethodsofinteractioncontrolhavebeeninvestigated.Theresearchhasmostlyconcernedsolid(vanetype)vortexgeneratorsandtranspirationmethodsofsuctionandblowing.Thisinvestigationconcernsinteractioncontrolusingair-jetstogeneratestreamwisevortices.Theeffectivenessofair-jetvortexgeneratorsincontrollingseparationhasbeenprovedinapreviousresearch.Thepresentpaperfocusesontheinfluenceofthevortexgeneratordiameterontheseparationregion.Itpresentstheresultsofexperimentalinvestigationsandprovidesnewguidelinesforthedesignofair-jetvortexgeneratorstoobtainmoreeffectiveseparationcontrol.

简介：突然注入一个房间的一口喷气驾驶的流动的不稳定的行为被解决axisymmetric数字地学习二维的可压缩的海军司烧方程。计算的系统是一个排出的过程在房间的下游的结束通过出口洞跟随的某个持续时间的激光脱离的一个模型。在计算，当象房间出口的喷气，它的持续时间，和直径的马赫数字那样的另外的参数被修理时，房间的轮廓被改变。在出口洞监视速度被用来在在冲击波和喷气之间的相互作用上调查形状的影响。作为结果，在房间出口的下游的结束的速度山峰价值和它的到达时间由房间的直径是坚定的，这被发现。

简介：Thetotalefficiencyofpowerplantsdependsontheenergyconversioninacombustorandaturbine.Considerablyhigherenergytransferratescanbeobtainedfromapulsedcombustion.butunsteadyflowofasinglejetcombustorreducestheturbineefficiency.Therefore.twopulsecombustorsweresetinparallelandconnectedtoasettlingchamberthatsuppliesaflowwithconstantpressuretotheturbine.Theaimofinvestigationspresentedhereisademonstrationoftechnicalfeasibilityforindustrialapplicationsandtoshowthebenefitsobtainedfromthepulsecombustors.

简介：在现在的学习，一个计算液体动力学工作被执行在超声的潮湿的空气喷气由冷凝作用调查冲击波的出现。不稳定的、可压缩的axisymmetric海军司烧方程被TVD(减少的全部的变化)解决在这研究的计划。数字模拟为低压力比率和各种各样的湿度被执行了。结果为低压力比率在超声的潮湿的空气喷气看冲击波的出现马赫磁盘什么时候不发生，取决于空气的湿度。

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简介：Theeffectofnozzlegeometryonsoniclineandcharacteristicsofsupersonicairjetwasstudied.Computationalfluiddynamicswasappliedinthisstudy.Theaxisymmetricnozzlegeometriesinvestigatedweretwodifferentcontourconvergingnozzles,twodifferentconicallyconvergingsharp-edgednozzlesandasharp-edgedorifice.Theresultsshowthatthesupersonicjetstructure,soniclineandstreamlinesinsupersonicjetarestronglyinfluencedbythenozzlegeometry,andthetotalpressurelossincreaseswiththeincreaseofMachdiskdiameter.Thepresentnumericalsimulationisaneffectivetooltoevaluatecompressibleflowsinsupersonicairjet.

简介：Atheoreticalstudywasconductedtocharacterizehydraulicjumpoflaminarcircularliquidjets.Theobjectiveofthisresearchwastodeterminethejumplocationinasimpleexplicitform,Theeffectsofmanyfactorswereinvestigatedincludingnozzlediameter,jetexitpressure,nozzle-to-platespacing,jetvelocityandReynoldsnumber,ItwasfoundthatthetheoreticaldatacollapsedwellovertherangeofjetReynoldsnumber500≤Re≤1800withpreviousdata.

简介：Whenthehigh-pressuregasisexhaustedtothevacuumchamberfromthenozzle,theunderexpandedsupersonicjetcontainedwiththeMachdiskisgenerallyformed.Theeventualpurposeofthisstudyistoclarifytheunsteadyphenomenonoftheunderexpandedfreejetwhenthebackpressurecontinuouslychangeswithtime.ThecharacteristicoftheMachdiskhasbeenclarifiedinconsiderationofthediameterandpositionofitbythenumericalanalysisinthispaper.ThesonicjetoftheexitMachnumberMe=1isassumedandtheaxisymmetricconservationalequationissolvedbytheTVDmethodinthenumericalcalculation.ThediameterandpositionoftheMachdiskdifferswiththeresultsofasteadyjetandtheinfluenceonthecontinuouslychangingofthebackpressureisevidencedfromthecomparisonwiththecaseofsteadysupersonicjet.