学科分类
/ 1
19 个结果
  • 简介:Abstract.OgrobjectinthisartlcleistodescribetbeGalerklnschemeandnonlin-eaxGalerkinschemefortheapproximationofnonlinearevolutionequations,andtostudythestabilityoftheseschemes.SpatialdiscretizatloncanbepedormedbyeitherGalerklnspectralmethodornonlinearGalerldnspectralmethod;timediscretizatlortisdonehyEulersin.heinewklchisexplicitorimplicitinthenonlinearterms.Accordingtothestabilityanalysisoftheaboveschemes,thestabilityofnonllneexGalerklnmethodisbetterthanthatofGalexklnmethod.

  • 标签: 非线性发展方程 非线性GALERKIN方法 稳定性分析 偏微分方程 耗散型方程
  • 简介:TheGalerkinandleast-squaresmethodsaretwoclassesofthemostpopularKrylovsubspacemethOdsforsolvinglargelinearsystemsofequations.Unfortunately,boththemethodsmaysufferfromseriousbreakdownsofthesametype:InabreakdownsituationtheGalerkinmethodisunabletocalculateanapproximatesolution,whiletheleast-squaresmethod,althoughdoesnotreallybreakdown,isunsucessfulinreducingthenormofitsresidual.Inthispaperwefrstestablishaunifiedtheoremwhichgivesarelationshipbetweenbreakdownsinthetwometh-ods.Wefurtherillustratetheoreticallyandexperimentallythatifthecoefficientmatrixofalienarsystemisofhighdefectivenesswiththeassociatedeigenvalueslessthan1,thentherestart-edGalerkinandleast-squaresmethodswillbeingreatrisksofcompletebreakdowns.Itappearsthatourfindingsmayhelptounderstandphenomenaobservedpracticallyandtoderivetreat-mentsforbreakdownsofthistype.

  • 标签: large linear systems iterative methods Krylov
  • 简介:Inthispaper,theminimaldissipationlocaldiscontinuousGalerkinmethodisstudiedtosolvetheellipticinterfaceproblemsintwo-dimensionaldomains.Theinterfacemaybearbitrarysmoothcurves.ItisshownthattheerrorestimatesinL2-normforthesolutionandthefluxareO(h2|logh|)andO(h|logh|^l/2),respectively.Innumericalexperiments,thesuccessivesubstitutioniterativemethodsareusedtosolvetheLDGschemes.Numericalresultsverifytheefficiencvandaccuracvofthemethod.

  • 标签: ELLIPTIC interface problem MINIMAL DISSIPATION local
  • 简介:几个Galerkin-Petrov方法,包括的多项式搭配和分析元素的集中在Dirichlet空间的Toeplitz操作员的搭配方法,被建立。特别地,如果基础和测试功能拥有某些圆形的对称,如此的方法收敛,这被显示出。给词调音:GalerkinPetrov方法;多项式搭配;分析元素搭配;Toeplitz操作员;Dirichlet空间

  • 标签: 狄利克雷空间 TOEPLITZ算子 Galerkin-Petrov法 收敛
  • 简介:Weperformanalysisforafiniteelementsmethodappliedtothesingularself-adjointproblem.Thismethodusescontinuouspiecewisepolynomialspacesforthetrialandthetestspaces.WefitthetrialpolynomialspacebypiecewiseexponentialsandweapplysoexponentiallyfittedGalerkinmethodtosingularself-adjomtproblembyapproximatingdrivingtermsbyLagrangepiecewisepolynomials,linear,quadraticandcubic.Wtmeasuretheerroeinmaxnorm.Weshowthatmethodisoptimalofthefirstorderintheerrorestimate,WealsogivenumericalresultsfortheGalerkinapproximation.

  • 标签:
  • 简介:NonlinearGalerkinmethodsarenewschemesforintegratingdissipativesystems:Inthepresentpaper,weobtaintheestimatestotherateofconvergenceofsuchmethodsforKuramoto-Sivashinskyequations.Inparticular,byanillustrativeexample,weshowthatnonlinearGalerkinmethodsconvergefasterthantheusualGalerkinmethod.

  • 标签: Nonlinear GALERKIN methods APPROXIMATE INERTIAL MANIFOLDS
  • 简介:Inthispaper,aunifiedmodelfortime-dependentMaxwellequationsindispersivemediaisconsidered.Thespace-timeDGmethoddevelopedin[29]isappliedtosolvetheunderlyingproblem.UnconditionalL2-stabilityanderrorestimateoforderOτr+1+hk+1/2areobtainedwhenpolynomialsofdegreeatmostrandkareusedforthetemporaldiscretizationandspatialdiscretizationrespectively.2-Dand3-Dnumericalexamplesaregiventovalidatethetheoreticalresults.Moreover,numericalresultsshowanultra-convergenceoforder2r+1intemporalvariablet.

  • 标签: 麦克斯韦方程组 有限元方法 色散媒质 时空 间断 数值结果
  • 简介:Inthispaper,weuseDaubechiesscalingfunctionsastestfunctionsfortheGalerkinmethod,anddiscussWavelet-GalerkinsolutionsfortheHamilton-Jacobiequations.ItcanbeprovedthattheschemesareTVDschemes.NumericaltestsindicatethattheschemesaresuitablefortheHamilton-Jacobiequations.Furthermore,theyhavehigh-orderaccuracyinsmoothregionsandgoodresolutionofsingularities.

  • 标签: HAMILTON-JACOBI方程 小波-珈辽金法 TVD法 多分辨率分析
  • 简介:AbstractAsystemofquasilinearcoupledequationswhicharisefromsimulationofcontaminationofgeologicnulearwasteinporousmediaisstudied.We’lldiscussGalerkinmethodforthemodelofcompressibleflowwithmoleculardiffusionanddispersion.Somenewtechniquesareintrocuedtoerroranalysis.Onlyonedimensionalcaseisconsidered.TheoptimalerrorestimateinbothL~2andH~1isproved.Acontributionofthispaperishowthedispersiontermcanbehandled,

  • 标签: COMPRESSIBLE flow CONTAMINATION of nuclear waste
  • 简介:Inthispaper,a-posteriorierrorestimatorsareproposedfortheLegendrespectralGalerkinmethodfortwo-pointboundaryvalueproblems.ThekeyideaistopostprocesstheGalerkinapproximation,andtheanalysisshowsthatthepostprocessimprovestheorderofconvergence.Consequently,weobtainasymptoticallyexactaposteriorierrorestimatorsbasedonthepostprocessingresults.Numericalexamplesareincludedtoillustratethetheoreticalanalysis.

  • 标签: Galerkin方法 后验误差估计 GALERKIN逼近 Legendre谱 维谱 边界值问题
  • 简介:ErrorestimatesofGalerkinmethodforKuramoto-Sivashingsky(K-S)equationinspacedimension≥3arederivedinthepaper.Theseresultsfurnishstrongevidenceforthecom-putationofthesolutions.

  • 标签: K-S equation GALERKIN method ERROR estimate.
  • 简介:为在多孔的媒介包括分子的散开和分散的一个可压缩的能溶合的排水量问题的一个联合混合有限元素和不连续的Galerkin方法被调查。那是说,有Raviart-Thomas空间的混合有限元素方法被用于流动方程,和运输一个人被对称的内部惩罚解决不连续的Galerkin(SIPG)近似。把插值和正式就职假设基于设计,superconvergence估计被获得。在分析期间,沿着高斯线的Darcy速度的延期也为集中在Galerkin过程在系数的评估被使用。

  • 标签: 间断GALERKIN方法 混合有限元方法 可压缩 混溶 合并 超收敛估计
  • 简介:Analternating-directionimplicit(ADI)Galerkinnuthodwithmovingfiniteelementspacesisformulatedforaclassofsecond-orderhyperbolicequationsintwospacevariables.AprioriH1-errorestimateisderived.

  • 标签:
  • 简介:AnA.D.I.Galerkinschemeforthree-dimensionalnonlinearparabolicintegro-differen-tialequationisstudied.Byusingalternating-direction,thethree-dimensionalproblemisreducedtoafamilyofsinglespacevariableproblems,thecalculationissimplified;byusingalocalapproxima-tionofthecoefficientsbasedonpatchesoffiniteelements,thecoefficientmatrixisupdatedateachtimestep;byusingRitz-Volterraprojection,integrationbypartandothertechniques,theinfluencecomingfromtheintegraltermistreated;byusinginductivehypothesisreasoning,thedifficultycomingfromthenonlinearityistreated.ForbothGalerkinandA.D.I.Galerkinschemesthecon-vergencepropertiesarerigorouslydemonstrated,theoptimalH~1-normandL~2-normestimatesareobtained.

  • 标签: NONLINEAR PARABOLIC integro-differential equation alternating-direction finite
  • 简介:Ahigh-orderleap-frogbasednon-dissipativediscontinuousGalerkintime-domainmethodforsolvingMaxwell'sequationsisintroducedandanalyzed.Theproposedmethodcombinesacenteredapproximationfortheevaluationoffluxesattheinterfacebetweenneighboringelements,withaNth-orderleap-frogtimescheme.Moreover,theinterpolationdegreeisdefinedattheelementlevelandthemeshisrefinedlocallyinanon-conformingwayresultinginarbitrarylevelhangingnodes.ThemethodisprovedtobestableundersomeCFL-likeconditiononthetimestep.Theconvergenceofthesemi-discreteapproximationtoMaxwell'sequationsisestablishedrigorouslyandboundsontheglobaldivergenceerrorareprovided.Numericalexperimentswithhigh-orderelementsshowthepotentialofthemethod.

  • 标签: GALERKIN法 麦克斯韦方程组 时间步长 跨越式 高阶 网格