简介：ThesedimentationsoftwocylindricalparticlesinthreedifferentinitialrelativepositionsarenumericallysimulatedusingthelatticeBoltzmannmethod.Themovementcharacteristicsandparticleinteractionsduringtheirsedimentationarepresentedanddiscussedindetail.Theresultsshowthat,(i)ifthetwoparticlesarereleasedparallelbutseparatedhorizontally,theypushawayeachother,rotateinwardsandseparatehorizontallyastheyfall;(ii)ifthetwoparticlesarereleasedparallelbutseparatedvertically,thesedimentationbehaviorcanbeclassifiedintothreestages:trailing,tumblingandseparating;(iii)ifthetwoparticlesarereleasedperpendicularbutseparatedvertically,thesedimentationbehaviorcanbecharacterizedas:trailingandrotating,touchingandsliding.Inordertovalidateoursimulation,experimentswerealsoconductedandtheresultsagreewellwiththenumericalones.

简介：Theinertiasofthefluidandtheinnercylinderincoaxialcylinderrheometer(CACR)havegreatinfluenceontheunsteadyflowofnon-Newtonianfluid.EvenfortheNewtonianfluidthereexistthesocalled'stressovershoot'phenomenon.Inthepresentarticlethisphenomenonwasstudiedindetailandamethodcorrectingthemeasuredresultsforanunsteadyflowintherheometerwasproposed.Itisfoundthattheinertiaeffectofthefluidcanbeignoredwhenthegapbetweencylindersissmall.

简介：根据本地平衡模型(LEM)，有大RichardsonZaki代表n的好粒子出现，在在床扩大和倒塌期间的某些条件下面，从有小n的粒子的不同动态行为。因为在那里的一个扩大过程可以是从分发者向上宣传的集中断绝，相反，为一个倒塌过程，可以而不是断绝有日益增多地拓宽和向上繁殖的连续转变地区。床高度变化和断绝踪迹的预言试验性地被验证了。

简介：Liquidsolid使流体化床在处理工业基于粒子尺寸，密度，和形状分开粒子的矿物质被使用。理解扩展的使流体化的床为精确地估计它的表演是重要的。使流体化的床的扩大特征被与铁矿石，铬铁矿，石英，和煤样品执行几个实验学习。把水用作液体媒介，实验被进行在使流体化的床上学习粒子尺寸，粒子密度，和表面的速度的效果扩大。试验性的数据被利用基于维的分析开发一个实验数学模型以粒子特征估计使流体化的床的扩大比率，操作并且设计参数。从数学模型获得的预言的扩大比率在对试验性的数据的好同意。

简介：在这份报纸，相对由液体的稳固的粒子的液体暂停的水动力学的理论途径和试验性的调查结果被报导并且讨论。为单个粒子硬币系统，优点和众所周知的实验关联的可能的差错被讨论。为二进制固体的混合暂停，试验性的证据被考察，能够成功地描述的途径观察到行为被报导。

简介：ThispaperstudiesRayleigh-B'enardconvectionofmicropolarfluidlayerheatedfrombelowwithrealisticboundaryconditions.AspecificapproachforstabilityanalysisofaconvectiveproblembasedonvariationalprincipleisappliedtocharacterizetheRayleighnumberforquitegeneralnatureofboundingsurfaces.TheanalysisconsistsofreplacingthesetoffieldequationsbyavariationalprincipleandtheexpressionsforRayleighnumberarethenobtainedbyusingtrialfunctionsatisfyingtheessential...

简介：TheconstitutiveequationforasemiconcentratedfibresuspensionintheOldroyd-Bfluidhasbeenderivedfromastatisticalmodelofsuchasuspensionbyemployingthemoleculartheoryforpolymericliquids.Tocircumventtheoreticaldifficultiesinviscoelasticfluidmechanics,severalsimplifiedmodelsareusedtoaccountfortheinteractionsoffibresandpolymermolecules.Someofmaterialfunctionsarecalculatedintermsoftheconstitutiveequation.

简介：ResearcheffortsmadesofartosimulatefibresuspensionflowsarelimitedtofibresuspensionsinNewtonianfluids.Thoughshortfibrecompositesaremostlymadeofpolymers,lackofsuitableconstitutiveequationsforfibresuspensionsinviscoelasticfluidsfrustratesattemptstosimulateflowsofthesesuspensions.ApreliminaryworkdonebytheauthorledtoaconstitutiveequationforsemiconcentratedfibresuspensionsintheOldroyd-Bfluid.Thispaperdescribesthemathematicalformulationoftheflowproblemsforsuchasuspensionandthenumericalproceduretosolvethem.Somenumericalresultsofflowpastasphereinatubearealsopresented.

简介：EffectsoftheorientationandapexangleonthesettlingvelocityofconicalparticlesinBinghamplas-ticfluidsarenumericallyinvestigatedoveraReynoldsnumberrangeof1≤Re≤100,Binghamnumberrangeof0≤Bn≤100,andconeanglerangeof20≤α≤150°.Governingequations(ofcontinuityandmomentum)aresolvednumericallyusingthefiniteelementmethodtoobtainvelocityandpressurefieldsthatarepostprocessedtoobtainvaluesofthedragcoefficien.Futthermore,theeffectofconeori-entationontheflowfieldisvisualizedandexploredintermsofstreamlinecontoursandthemorphologyofyielded/unyieldedregions.Finally,theobtainedvaluesofdragarecorrelatedviaasimplepredictiveexpressionintermsofthemodifiedReynoldsnumber.Theeffectoftheconeangleondragisfoundtobemoderatebecausethedragforceactingonthelateralsurfaceisasmallfractionoftheoveralldrag.

简介：Fluid-particleinteractionunderpinsimportantbehaviorofgranularmedia.Particle-scalesimulationmayhelptoprovidekeymicroscopicinformationgoverningtheinteractionandofferbetterunderstandingofgranularmediaasawhole.Thispaperpresentsacoupledcomputationalfluiddynamicsanddiscreteelementmethod(CFD-DEM)approachforthispurpose.ThegranularparticlesystemismodeledbyDEM,whilethefluidflowissimulatedbysolvingthelocallyaveragedNavier-StokesequationwithCFD.ThecouplingisconsideredbyexchangingsuchinteractionforcesasdragforceandbuoyancyforcebetweentheDEMandCFD.Theapproachisbenchmarkedbytwoclassicgeomechanicsproblemsforwhichanalyticalsolutionsareavailable,andisfurtherappliedtothepredictionofsandheapformationinwaterthroughhopperflow.Itisdemonstratedthatthekeycharacteristicofgranularmaterialsinteractingwithporewatercanbesuccessfullycapturedbytheproposedmethod.

简介：ThispaperestablishesthevelocityfieldandtheadequateshearstresscorrespondingtothemotionofanOldroyd-BfluidbetweentwoinfinitecoaxialcircularcylindersbymeansoffiniteHankeltransforms.Theflowofthefluidisproducedbytheinnercylinderwhichappliesatime-dependentlongitudinalshearstresstothefluid.Theexactanalyticalsolutions,presentedinseriesformintermsofBesselfunctions,satisfyallimposedinitialandboundaryconditions.ThegeneralsolutionscanbeeasilyspecializedtogivesimilarsolutionsforMaxwell,secondgradeandNewtonianfluidsperformingthesamemotion.Finally,somecharacteristicsofthemotionaswellastheinfluenceofthematerialparametersonthebehaviorofthefluidmotionaregraphicallyillustrated.

简介：Astandardconservationformisderivedinthispaper.ThehyperbolicityofHelbing’sfluiddynamictrafficflowmodelisproved,whichisessentialtothegeneralanalyticalandnumericalstudyofthismodel.Onthebasisofthisconservationform,alocaldiscontinuousGalerkinschemeisdesignedtosolvetheresultingsystemefficiently.Theevolutionofanunstableequilibriumtrafficstateleadingtoastablestop-and-gotravelingwaveissimulated.Thissimulationalsoverifiesthatthemodelistrulyimprovedbytheintroductionofthemodifieddiffusioncoefficients,andthushelpstoprotectvehiclesfromcollisionsandavoidetheappearanceoftheextremelylargedensity.

简介：Inthispaper,multifractalanalysistogetherwithwavelettransformmodulusmaxima(WTMM)methodisusedtoanalyzethefluctuatingsignalsofcirculatingfluidizedbed(CFB).Singularityspectrumshowsthatthegas-particleflowinCFBhasmultifractalcharacter.Motionbehavioroftheparticle-fluidsystemofCFBcanbedescribedbysingularityspectrum.Intermittencyindexcanbeusedtodeterminethetransitionofflowregimefromfastfluidizationtopneumaticconveying.

简介：Toanalyzeanddepictcomplicatedfluidbehaviorsinfracturedporousmediawithvariablypermeablematrix,anintegrateddiscretecomputationalalgorithmisproposedbasedonlatticeBoltzmannmethod(LBM).Thispapercombineswiththeexternalforcemodelandstatisticalmaterialphysicstoeffectivelydescribethefeaturechangeswhilethefluidpassesthroughthefractureswithinthepermeablematrix.Asanapplicationexample,atwodimensionalrocksampleisreconstructedusingthedigitalimageandcharacterizedwithdifferentfeaturevaluesateachLBMgridtodistinguishpores,impermeableandpermeablematrixbystatingitslocalphysicalproperty.ComparedwiththeconventionalLBM,theresultsdemonstratetheadvantagesofproposedalgorithminmodelingfluidflowphenomenoninfracturedporousmediawithvariablypermeablematrix.

简介：Thisinvestigationdealswiththeeffectsofslip,magneticfield,andnonNewtonianflowparametersontheflowandheattransferofanincompressible,electricallyconductingfourth-gradefluidpastaninfiniteporousplate.Theheattransferanalysisiscarriedoutfortwoheatingprocesses.Thesystemofhighlynon-lineardifferentialequationsissolvedbytheshootingmethodwiththefourth-orderRunge-Kuttamethodformoderatevaluesoftheparameters.TheeffectiveBroydentechniqueisadoptedinordertoimprovetheinitialguessesandtosatisfytheboundaryconditionsatinfinity.Anexceptionalcross-overisobtainedinthevelocityprofileinthepresenceofslip.Thefourth-gradefluidparameterisfoundtoincreasethemomentumboundarylayerthickness,whereastheslipparametersubstantiallydecreasesit.Similarly,thenon-Newtonianfluidparametersandthesliphaveoppositeeffectsonthethermalboundarylayerthickness.

简介：Spreadingofnanofluidsonsolidsubstratewasstudiedviamoleculardynamicssimulations.Simulationmodelsfortwoimmisciblefluids(oilandwaterbasednanofluids)confinedinaslitbetweentwoplanarsolidwallsweresetup.Theinfluenceofthevolumeconcentrationofthenanoparticlesonthethree-phasecontactlinemotionwasinvestigated.Wefoundthatthelargervolumeconcentrationresultsinmorevisiblenanoparticleadsorptiononsolidsurface.Thisefectfurtherinducesanadvancingdisplacementofthecontactlinecomparedwiththemeniscusprofilesinlowconcentrationcaseandthatwiththeabsenceofnanoparticles.Thesefindingsareconsistentwiththepreviousexperimentalandtheoreticalresultsandprovidetheatomic-scaleunderstandingonnanofluidspreading.

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简介：Inthiswork,theborescopicparticleimagevelocimetry(BPIV)techniquewasappliedtoabubblinggas-solidfluidizedbed,andtheresultswerecomparedwithpublishedpositronemissionparticletracking(PEPT)measurementdata.Beforeperformingtheexperiments,thesensitivityoftheBPIVresultstotheilluminationpower,lightreflectivityoftheparticles,andlocationoftheborescopewasalsoinvestigated.TheBPIVandPEPTresultswereinfairagreement;however,somediscrepancieswereobserved.ThedifferencebetweenthetwosetsofresultsweremainlycausedbytheintrusivenessofBPIV,thefactthatthelocalsolidsvolumefractionwasnotaccountedforintheBPIVanalysis,andtheintrinsicdifferencesofthesetwomethods.Therefore,measurementofthelocalsolidsvolumefractionwiththeborescopeishighlyrecommendedforfurtherdevelopmentoftheBPIVmethod,whichwillalsoenablemeasurementofthelocalsolidsmassfluxesinsidedensegas-solidfluidizedbeds.

简介：NanocrystallineSnO2wassynthesizedbydirectmixingandgrindingofSnCI4-5H2OandNaOHatroomtemperature,followedbycalcinationatdifferenttemperaturesfordifferenttimesinair.ProductsampleswerecharacterizedbyX-raydiffractionandtransmissionelectronmicroscope,revealingthattheamorphousprecursorSnO2wastransformedtocrystalsat200℃for3h,andthattheaverageparticlesizeincreaseduponraisingthecalciningtemperatureorprolongingthecalciningtime.Themechanismofthephasetransformationoftheproductsisdiscussed.

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