简介：Inthisarticletheemphasiswasgiventothediscussionoftheeffectsofdiameterratioandswirlingoninstabilitycharacterforthegas/liquidcoaxialjetusedbyLiao,etal.[1].Theresultsindicatethatthefinitediameterratiomarkedlyincreasesthemaximumgrowthrate,themostunstablewavenumber,aswellasthecutoffwavenumber.Itimpliesthatthefinitediameterratiowillleadtotheliquidjetbreakuplengthshorterandtheliquiddropsizesmaller.Theeffectoftheswirlingjetsismuchmorecomplex:fortheaxisymmetricperturbationmode,theswirlingenhancestheflowstability,forhelicalperturbation,thedominantinstabilitymodeoccursatn<0.Anditisfoundthatinlongwaveregionthereexistsanewkindofinstabilitymodesatn=1thatwasnotmentionedinLiaoetal.'sarticle.Forthisnewmode,thereappearsadominatedswirlingratioatwhichtheflowhasthemaximumgrowthrate.

简介：Atypeofportwithamovablecoverisdesignedtoincreaseinitialdilutionandpreventseawaterandsedimentsfromintrudingintooutfallsystems.Horizontalradialjetspro-ducedbythistypeofportinacurrentareinvestigatedexperimentallyandtheoretically.TheanalysisbasedonReynolds’equationsandself-similarityhypothesisshowsthatthemaximumve-locityofradialjetsdecayswithr-1.5.Therelationshipsbetweenthewidth,thickness,averagedi-lutionofasubmergedwastefieldalongflow,andtheparametersoftheport,jetandambientareestablishedquantitativelyandverifiedbyexperiments.Itisdemonstratedthatthedilutionofhorizontalradialjetsismuchhigherthanthatofverticalroundjetsandthesurfaceboilpointoftheformerismuchmoredistantthanthatofthelatter.

简介：垂直地在免费表面上侵犯的一口2D槽喷气的流动特征被大埃迪模拟(LES)数字地与一个动态Sub-GridScale(SGS)模型一起调查。σ-坐标转变被介绍印射深度变量物理领域到一件深度制服计算领域。裂口操作员计划，把答案过程切成移流，散开和压力繁殖步，被采用解决即时速度和压力地。一个充分非线性的Lagrange-Euler方法被用来计算免费表面举起。数字结果证明喷气在Eestablished流动(ZEF)的地区保留你方类似，当喷气的骚乱逐渐地变从时对各向同性在表面冲击(ZSI)的地区各向异性。当喷气接近免费表面时，中心线速度很快减少并且流动被免费表面偏斜。二口对称的表面喷气在水平喷气(ZHJ)的地区被形成。超高的AnapproximateGuassian分发也在免费表面上被形成。Thecomputed结果在对可得到的试验性的数据的好同意。

简介：ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＳＯＦＷＨＯＬＥＦＩＥＬＤＢＥＨＡＶＩＯＲＦＯＲＲＯＵＮＤＢＵＯＹＡＮＴＪＥＴＬｉＷｅｉ，ＨｕａｉＷｅｎ－ｘｉｎ（ＷｕｈａｎＵｎｉｖｅｒｓｉｔｙｏｆＨｙｄｒａｕｌｉｃａｎｄＥｌｅｃｔｒｉｃＥｎｇｉｎｅｅｒｉｎｇ，...

简介：Inthispaper,astudyofthehigh-speedgasjetofarocketnozzleunderwaterwascarriedoutusingcommerciallyavailableCFDsoftwareFLUENTwithit'suser-defined-function.Thevolumeoffluidtechniquebasedonfinitevolumemethodwasadoptedtosolvethetime-dependentmultiphaseflowincludingacompressiblephase,andthePISOalgorithmwasincluded.Thecomputedresultsshowthatthisproblemwascalculatedsuccessfully.Thegasbubblebehindthenozzle,andthewavestructureexistinginhighlycompressedgasinwaterwerecapturedaccurately.

简介：Asanewjettechnologydevelopedinrecentyears,thesupercriticalcarbondioxide(SC-CO2)jettechnologyenjoysmanyadvantageswhenappliedinoilandgasexplorations.InordertostudythepropertiesandparametricinfluencesoftheSC-CO2jet,theflowfieldsoftheSC-CO2jetaresimulatedusingthecomputationalfluiddynamicsmethod.TheflowfieldoftheSC-CO2iscomparedwiththatofthewaterjet.TheinfluencesofseveralparametersontheflowfieldoftheSC-CO2jetarestudied.Itisindicatedthatlikethewaterjet,thevelocityandthepressureoftheSC-CO2jetcouldbeconvertedtoeachother,andtheSC-CO2jetcangenerateasignificantimpactpressureonthewall,theSC-CO2jethasastrongerimpactpressureandahighervelocitythanthoseofthewaterjetunderthesameconditions,themaximumvelocityandtheimpactpressureoftheSC-CO2jetincreasewiththeincreaseofthenozzlepressuredrop,underthestimulationconditionofthisstudy,theinfluenceoftheSC-CO2temperatureontheimpactpressurecanbeneglectedinengineeringapplications,whilethemaximumvelocityoftheSC-CO2jetincreaseswiththeincreaseofthefluidtemperature.ThispapertheoreticallyexploresthepropertiesoftheSC-CO2jetflowfield,andtheresultsmightprovideatheoreticalbasisfortheapplicationoftheSC-CO2jetinoilandgaswelldrillingsandfracturingstimulations.

简介：ByusingtheReynoldsStressClosureModel(RSM),turbulentCounter-Gradient-Transport(CGT)phenomenonwasnumericallyinvestigatedinasymmetricflowwithajet,andthecomputationalresultswerecomparedwithexperimentaldata.ThecomputationalresultsshowthatthenegativeturbulentenergyproductiononlyappearsatsomecertainstationsinCGTregion,thisfactindicatesthattheCGTphenomenonexistsmorewidelythanthenegativeturbulentenergyproduction;whiletheCGTregionexistsallalong,itgraduallyshrinksinthefavorablepressuregradientzoneuntilthepositionofthewingcentralpartisreached,whereitvanishes,butitappearsintheadversepressuregradientregion;inaddition,thelocationintheflowwhereuv=0switchedsides,relativetowhere()U/()y=0,fromfavorablepressuregradienttoadversepressuregradient.ThepressuregradienttakesanimportanteffectontheregionofnegativeturbulentenergyproductionandCGT.

简介：

简介：HighlyunderexpandedaxisymmetricjetwassimulatedusingtheRunge-KuttaDiscontinuousGalerkin(RKDG)finiteelementmethod,which,basedontwo-dimensionalconservationlaws,wasusedtosolvetheaxisymmetricEulerequations.Thecomputedresultsshowthatthecomplicatedflowfieldstructuresofinterest,includingshockwaves,slipstreamsandthetriplepointobservedinexperimentscouldbewellcapturedusingtheRKDGfiniteelementmethod.Moreover,comparisonsoftheMachdisklocationexhibitexcellentagreementsbetweenthecomputedresultsandexperimentalmeasurements,indicatingthatthismethodhashighcapabilityofcapturingshockswithoutnumericaloscillationandartificialviscosityoccurringnearthediscontinuouspoint.

简介：ACFDsimulationisperformedforaparticle-ladenplanarjetflow.TheReynoldsnumberis8300,andtheinitialparticlediameteris1μm.LargeEddySimulation(LES)isemployedtocalculatetheflowfield,andtheTaylor-seriesexpansionmomentmethod(TEMOM)isadoptedtodealwiththebalanceequationofparticlecoagulationandbreakage.Theshear-inducedcoagulationkernel,power-lawbreakagekernelandsymmetricfragmentdistributionfunctionareinvolved.Thepredictionofthedistributionofthemeanstreamwisevelocityofthejetisingoodagreementwithexperimentaldata.Theevolutionofparticlenumberconcentration,volumeconcentration,polydispersity,particlediameterandstandardgeometricdeviationisdiscussedindetail.Theresultsshowthatasthejettravelsdownstream,theparticlenumberconcentrationandvolumeconcentrationdecrease,whiletheirspansbecomewider.Thepolydispersityandparticlediameterareverylargeintheshearlayersattheupstreamandinthecoreofvortexstructuresatthedownstream.Theparticlestandardgeometricdeviationchangeswithintherangeof1.32≤σg≤1.96,andincreasessharplyintheshearlayers.Allvariablesapproachthesteady-stateastimeprogresses.