学科分类
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16 个结果
  • 简介:Cahn-Hilliard阶段地的数字近似当模特儿因为二阶段的不可压缩的流动在这份报纸被考虑。几有效并且为联合非线性的Cahn-Hilliard阶段地的精力马厩时间discretization计划为匹配的密度盒子和变量的系统密度大小写被构造,并且被显示满足类似于连续精力法律的分离精力法律。

  • 标签: 不可压缩流 能源计划 流动模型 稳定 位场 d相
  • 简介:Humanimmunodeficiencyvirus(HIV)hashadaninsightfulimpactaboutthestateofhealthinessofhumanimmunesystem.Duetogreatimprovementindrugtherapy,HIVinfectionshavebeenreducedby17%overthepasteightyears.IthasbeenprovedthatmosteffectivetreatmentHAART(HighlyActiveAntiRetroviralTherapy)mainlycontrolsthediseasesprogressionbutitdoesnoteradicatethediseasescompletely.ReverseTranscriptaseInhibitordrugsspeciallyassociatedwithvirusspecificCytotoxicT-Lymphocyte(CTL)thatdeclineswithdiseaseprogression.CTLresponsesagainstAIDSpathogenesiscouldbepotentialinthedynamicsofvirusreplication,recognitionandclearanceofinfectedcells.InthisresearcharticleamathematicalmodelhasbeenproposedonthebasisofCTLresponsesuppressioninthechronicphaseofinfectionduetopresenceofvirus.WealsoconsiderthegrowthoftheviruspopulationfromtheinfectedCD4~+Tcellsbuddingprocessandfromtheotherinfectedcellslikemacrophagesandthymocytes.Ouranalyticalandnumericalstudiesareconsistentwithexistingobservationsfromalliedareas.

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  • 简介:Two-phase,immiscible,incompressibleflowinporousmediaisgovernedbyasystemofnonlinearpartialdifferentialequations.Inmostpracticalapplicationsconvectionphysicallydominatesdiffusion,andtheobjectofthispaperistodevelopafinitedifferencemethodcombinedwiththemethodofcharacteristicsandthelumpedmassmethodtotreattheparabolicequationofthedifferentialsystem.Thismethodisshownsatisfythemaximumprincipleanditserroranalysisispresented.

  • 标签: IMMISCIBLE INCOMPRESSIBLE PROBLEM maximum PRINCIPLE numerical
  • 简介:Inthispaperweshallgivethecharacteristicdifferencemethodsfortwophasedisplacemeatprobleminnaturallyfracturedreservoirs.Weshallprovetheexistence,uniquenessoftheapproximatesolutionandaprioridiscreteL2-errorestimates.

  • 标签: DIFFERENCE METHOD TWO-PHASE DISPLACEMENT naturally fructured
  • 简介:Twophase,miscible,incompressibleflowinporousmediaisgovernedbyasystemofnonlinearpartialdifferentialequations.Manynumericalmethodshavebeengivenbydidierentauthorstothissystem,hutthesemethodsneedveryhighregularityconditions.Actualty,inmostpracticalapplicationstheseregularityconditionscouldn'tbesatisfied.Inthispaper,theproblemofdiscontinuouscoefficientswithlowerregularityconditionsisconsideredandtheerrorestimatesaredemonstrated.

  • 标签: 有限元 近似值 不联续系数 混合置换
  • 简介:Thispaperconsidersaperturbedrenewalriskprocessinwhichtheinter-claimtimeshaveaphase-typedistributionunderathresholddividendstrategy.Integro-differentialequationswithcertainboundaryconditionsforthemoment-generatingfunctionandthemthmomentofthepresentvalueofalldividendsuntilruinarederived.Explicitexpressionsfortheexpectationofthepresentvalueofalldividendsuntilruinareobtainedwhentheclaimamountdistributionisfromtherationalfamily.Finally,wepresentanexample.

  • 标签: 风险模型 干扰 相带 矩生成函数 风险过程 积分方程
  • 简介:Themiscibledisplacementofoneincompressiblefluidbyanotherinaporousmediumisconsideredinthispaper.Theconcentrationissplitinafirst-orderhyberbolicequationandahomogeneousparabolicequationwithineachlimestep.ThepressureandUsvelocityfieldiscomputedbyamixedfiniteelementmethod.Optimalorderestimatesarederivedforthenodiffusioncaseandthediffusioncase.

  • 标签: MISCIBLE displacement PROBLEM VISCOSITY SPLITTING method.
  • 简介:Tow-phaseflowmixedvariationalformulationsofevolutionfiltrationproblemswithseawaterintrusionareanalyzed.Adualmixedfractionalflowvelocity-pressuremodelisconsideredwithanair-freshwaterandafreshwater-seawatercharacterization.Foranalysisandcomputationalpurposes,spatialdecompositionsbasedonnonoverlappingmultidomains,aboveandbelowthesealevel,arevariationallyintroducedwithinternalboundaryfluxesdualizedasweaktransmissionconstraints.Further,parallelaugmentedandexactlypenalizeddualityalgorithms,andproximationsemi-implicittimemarchingschemes,areestablishedandanalyzed.

  • 标签: 海水入侵 变分分析 混合 两相流 过滤 演化
  • 简介:Forcompressibletwo-phasedisplacementproblem,themodifiedupwindfinitedifferencefractionalstepsschemesareputforward.Sometechniques,suchascalculusofvariations,commutativelawofmultiplicationofdifferenceoperators,decompositionofhighorderdifferenceoperators,thetheoryofpriorestimatesandtechniquesareused.OptimalorderestimatesinL2normarederivedfortheerrorintheapproximatesolution.Thismethodhasalreadybeenappliedtothenumericalsimulationofseawaterintrusionandmigration-accumulationofoilresources.

  • 标签: 收敛性 二相位移 二维空间压缩 偏微分方程 有限逆向修正差分算法
  • 简介:EQrot1nonconformingfiniteelementapproximationtoaclassofnonlineardualphaselaggingheatconductionequationsisdiscussedforsemi-discreteandfully-discreteschemes.Byuseofaspecialproperty,thatis,theconsistencyerrorofthiselementisoforderO(h2)oneorderhigherthanitsinterpolationerrorO(h),thesupercloseresultsoforderO(h2)inbrokenH1-normareobtained.Atthesametime,theglobalsuperconvergenceinbrokenH1-normisdeducedbyinterpolationpostprocessingtechnique.Moreover,theextrapolationresultwithorderO(h4)isderivedbyconstructinganewinterpolationpostprocessingoperatorandextrapolationschemebasedontheknownasymptoticexpansionformulasofEQrot1element.Finally,optimalerrorestimateisgainedforaproposedfully-discreteschemebydifferentapproachesfromthepreviousliterature.

  • 标签: 热传导方程 非协调 非线性 有限元方法 双相 插值误差
  • 简介:TheembeddedboundarymethodforsolvingellipticandparabolicproblemsingeometricallycomplexdomainsusingCartesianmeshesbyJohansenandColella(1998,J.Comput.Phys.147,60)hasbeenextendedforellipticandparabolicproblemswithinteriorboundariesorinterfacesofdiscontinuitiesofmaterialpropertiesorsolutions.Secondorderaccuracyisachievedinspaceandtimeforbothstationaryandmovinginterfaceproblems.Themethodisconservativeforellipticandparabolicproblemswithfixedinterfaces.Basedonthismethod,afronttrackingalgorithmfortheStefanproblemhasbeendeveloped.Theaccuracyofthemethodismeasuredthroughcomparisonwithexactsolutiontoatwo-dimensionalStefanproblem.Thealgorithmhasbeenusedforthestudyofmeltingandsolidificationproblems.

  • 标签: 抛物问题 椭圆形 边界法 材料系统 接口 STEFAN问题