简介:Inthispaper,weareconcernedwithuniformsuperconvergenceofGalerkinmethodsforsingularlyperturbedreaction-diffusionproblemsbyusingtwoShishkin-typemeshes.Basedonanestimateoftheerrorbetweensplineinterpolationoftheexactsolutionanditsnumericalapproximation,aninterpolationpost-processingtechniqueisappliedtotheoriginalnumericalsolution.Thisresultsinapproximationexhibitsuperconvergencewhichisuniformintheweightedenergynorm.Numericalexamplesarepresentedtodemonstratetheeffectivenessoftheinterpolationpost-processingtechniqueandtoverifythetheoreticalresultsobtainedinthispaper.
简介:集中和为在一个维的设定的一个不可思议地使不安的模型问题的不连续的Galerkin(DG)方法的超级集中性质被学习。由与DG答案的适当地选择的数字踪迹,存在和唯一使用DG方法,最佳的顺序L2错误界限,和2p+i顺序数字踪迹斧子的超级集中建立了。数字结果显示DG方法不甚至在一致网孔下面生产任何摆动。数字实验证明在一致网孔下面,获得数字踪迹的一致超级集中似乎不可能。不过,对所谓的Shishkin类型的实现的感谢协调,一致2p+1顺序超级集中数字地被观察。
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简介:Inthispaper,weconsiderthelocaldiscontinuousGalerkinmethod(LDG)forsolv-ingsingularlyperturbedconvection-diffusionproblemsinone-andtwo-dimensionalset-tings.TheexistenceanduniquenessoftheLDGsolutionsareverified.Numericalex-perimentsdemonstratethatitseemsimpossibletoobtainuniformsuperconvergencefornumericalfluxesunderuniformmeshes.Thankstotheimplementationoftwo-typedif-ferentanisotropicmeshes,i.e.,theShishkinandanimprovedgrademeshes,theuniform2p+1-ordersuperconvergenceisobservednumericallyforbothone-dimensionalandtwo-dimensionalcases.
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简介:Thispaperdealswithanalyticandnumericaldissipativityandexponentialstabilityofsingularlyperturbeddelaydifferentialequationswithanyboundedstate-independentlag.Sufficientconditionswillbepresentedtoensurethatanysolutionofthesingularlyperturbeddelaydifferentialequations(DDEs)withaboundedlagisdissipativeandexponentiallystableuniformlyforsufficientlysmallε>0.Wewillstudythenumericalsolutiondefinedbythelinearθ-methodandone-legmethodandshowthattheyaredissipativeandexponentiallystableuniformlyforsufficientlysmallε>0ifandonlyifθ=1.
简介:Inthiswork,asingularlyperturbedtwo-pointboundaryvalueproblemofconvection-diffusiontypeisconsidered.AnhpversionfiniteelementmethodonastronglygradedpiecewiseuniformmeshofShishkintypeisusedtosolvethemodelproblem.Withtheanalyticassumptionoftheinputdata,itisshownthatthemethodconvergesexponentiallyandtheconvergenceisuniformlyvalidwithrespecttothesingularperturbationparameter.
简介:在这份报纸,我们考虑充分分离的本地不连续的Galerkin方法,在第三命令前进的明确的Runge-Kutta时间被联合的地方。为一个维的时间依赖者有边界层的不可思议地使不安的问题,我们将证明结果的计划具有在本地稳定性的好行为不仅,而且有双optimal本地人错误估计。它是说,集中率在空间和时间是最佳的,并且截止子域的宽度也是将近最佳的,如果在各中间的舞台的边界条件以一个合适的方法被给。数字实验也被给。