简介:Thispaperdescribesanovelsharpinterfaceapproachformodelingthecavitationphenomenainincompressibleviscousflows.Aone-fieldformulationisadoptedforthevapor-liquidtwo-phaseflowandtheinterfaceistrackedusingavolumeoffluid(VOF)method.PhasechangeattheinterfaceismodeledusingasimplificationoftheRayleigh-Plessetequation.Interfacejumpconditionsinvelocityandpressurefieldaretreatedusingalevelsetbasedghostfluidmethod.Thelevelsetfunctionisconstructedfromthevolumefractionfunction.Amarchingcubesmethodisusedtocomputetheinterfaceareaattheinterfacegridcells.Aparallelfastmarchingmethodisemployedtopropagateinterfaceinformationintothefield.Adescriptionoftheequationsandnumericalmethodsispresented.Resultsforacavitatinghydrofoilarecomparedwithexperimentaldata.
简介:FlowsaroundacircularcylinderdisplayinganunsteadyvortexsheddingprocessattheReynoldsnumbersof1000,3900and1×104arestudiedusingafinite-volumeTotalVariationDiminishing(TVD)schemeforsolvingtheUnsteadyReynolds-AveragedNavier-Stokes(URANS)equations.AnElementalVelocityVectorTransformation(EVVT)approachisproposedforthelocalnormalandtangentialvelocitytransformationattheinterfacesofmainandsatelliteelements.Thepresentedmethodisvalidatedbycomparingwiththeavailableexperimentaldataandnumericalresults.Itisshownthatthetwo-dimensionalTVDfinitevolumemethodwiththeRenormalizationGroup(RNG)turbulencemodelcanbeusedtodeterminehydrodynamicforcesandcapturesvortexsheddingcharacteristicsverywell.
简介:Duetotheintricatestructureofporousmedia,themacroscopicpetrophysicaltransportpropertiessuchasthepermeabilityandthesaturationusedforthereservoirpredictionalsoshowaverycomplexnatureandaredifficulttoobtain.Thus,abetterunderstandingoftheinfluenceoftherockstructureonthepetrophysicaltransportpropertiesisimportant.Inthispaper,wepresentauniversalfinitevolumeelementmodelingapproachtoreconstructthethreedimensionalporemodelsfromthemicro-CTimagesbasedonthecommercialsoftwareMimicsandICEM,priortotheporenetworkmodelbasedonsomebasicassumptions.Moreover,tetrafinitevolumeelementsarepileduptorealizethegeometryreconstructionandthemeshingprocess.Comparedwiththeformermethods,thisprocessavoidsthetremendouslylargestoragerequirementforthereconstructedporousgeometryandthefailuresofmeshingthesecomplexpolygongeometries,andatthesametimeimprovesthepredictionsofpetrophysicaltransportbehaviors.ThemodelistestedontwoBereasandstones,foursandstonesamples,twocarbonatesamples,andoneSyntheticSilica.Single-andtwophaseflowsimulationsareconductedbasedontheNavier-StokesequationsintheFluentsoftware.Goodagreementsareobtainedonboththenetworkstructuresandpredictedsingle-andtwo-phasetransportpropertiesagainstbenchmarkexperimentaldata.