简介：Aprocessfornumericalanalysisofradialcirculationdistributionofpropellerbladeisproposedandpresented.Itisbasedontheresultsofnumericalsimulationofthevelocityfieldaroundpropellerbladesandinthewake.Thewell-knowntraditionalmethodusingtangentialvelocitydatainthewakeandapplyingStockes'stheoremwasalsoexaminedintheinvestigation.Theresultsfromtwoapproachesarecomparedwitheachother.Itisfoundthatifthetraditionalwayisutilized,inmanycasesanunexpected'hump'appearsinthecirculationdistributionatcertainouterradius.Theauthorscalculatedthecirculationsdirectlyaroundbladesections,anditisreferredasdirectmethod.Theunexpectedhumpofthecirculationdistributiondisappearsintheresultsofdirectmethod.Thisarticlealsodiscussesthereasonsoftheappearanceoftheunexpectedhumpintraditionalapproach.Thedirectmethodisproposedtohaveapotentialinanalyzingorverifyingtheradialroaddistributionfordesignedpropellerandthenumericalanalysisinsteadofexperimentalvalidationforcirculationdistributioncanbeasatoolinthepropellerdesignprocess.

简介：Amulti-bubbledynamicscodeaccountingforgasdiffusionintheliquidandthroughthebubblewallwasdevelopedandusedtostudythemodificationofabubblenucleipopulationdynamicsbyapropeller.ThepropellerflowfieldwasobtainedusingaReynolds-AveragedNavier-Stokes(RANS)solverandbubblenucleipopulationswerepropagatedinthisfield.Thenumericalpro-cedureenabledestablishmentofthepossibilityofproductionbehindthepropellerofrelativelylargevisiblebubblesstartingfromtypicaloceannucleisizedistributions.Theresultinglargerbubblesareseentoclusterinthebladewakesandtipvortices.Parametricinvestigationsoftheinitialnucleisizedistribution,thedissolvedgasconcentration,andthecavitationnumberwereconductedtoide-ntifytheireffectsonbubbleentrainmentandtheresultantvoidfractionsandbubbledistributionmodificationsdownstreamfromthepropeller.Imposedsyntheticturbulence-likefluctuationsuntotheaverageRANSflowfieldwerealsousedtostudytheeffectavera-gingintheRANSprocedurehasontheresults.

简介：TheFilteringGridScale(FGS)ofsub-gridscalemodelsdoesnotmatchwiththetheoreticalProperFGS(PFGS)becauseoftheimpropermesh.Therefore,properLargeEddySimulation(LES)Meshisverydecisiveforbetterresultsandmoreeconomicalcost.Inthiswork,thepurposeistoprovideanadaptivecontrolstrategyforproperLESmeshwithturbulencetheoryandCFDmethods.AnewexpressionofPFGSisproposedonthebasisof-5/3lawofinertialsub-rangeandthepropermeshofLEScanbebuiltdirectlyfromtheadjustmentofRANSmesh.Abenchmarkofthebackwardfacingstepflowatisprovidedforapplicationandverification.Therearethreekindsofmeshsizes,includingtheRANSmesh,LAM(LESofadaptive-controlmesh),LFM(LESoffinemesh),employedhere.ThegridnumberofLAMissmallerthanthoseofLFMevidently,andtheresultsofLAMareinagoodagreementwiththoseofDNSandexperiments.ItisrevealedthattheresultsofLAMareveryclosetothoseofLFM.Theconclusionsprovidepositiveevidencesforthenovelstrategy.

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.

简介：为测量处理方法的一幅图象即时二维(2D)在高水泡数字密度的本地空部分被建议。它基于计算在水泡羽毛图象和真实空部分的局部地平均的亮度之间的关联。方法从设想的图象用本地空部分的2D分发被测试，在在局部地平均的亮度和设计虚空部分之间的关联被在各种各样的条件下面介绍水泡图象的重叠概率的理想导出的地方。这研究被用来与方面比率of1.0学习冒泡的流动的行为1.5，和2.0。现在的方法被用于即时测量。为有产生流动率的三个不同水泡的三不同方面比率的水泡羽毛的空部分在冒泡的流动的行为上为水泡的效果的澄清被测量。煤气的流动率上的空部分的相关性被测量并且与其它相比源于文学。在我们的实验的范围，坦克的方面比率不仅影响羽毛的结构，而且在坦克的煤气的流动率影响羽毛的结构，这被观察。