简介：Acouplingmethodoffiniteelementandinfinitelargeelementisproposedforthenumericalsolutionofaneigenvalueprobleminunboundeddomainsinthispaper.Withsomeconditionssatisfied,theconsideredproblemisprovedtohavediscretespectra.Severalnumericalexperimentsarepresented.Theresultsdemonstratethefeasibilityoftheproposedmethod.

简介：Inthispaper,thedynamicresponseofundersea-+towedsystemsisnumericallysimulated.Atwobodytowedsystemisespeciallyconsideredindetail.Thefactorsinfluencingtheheaveoftowed-bodies,suchastheweightofthetowed-body(inseawater),thelengthandtheweight(inseawater)perunitlengthofthecablebetweentowed-bodiesandtowingship,areinvestigatedindetail.Calculationsshowthatthetwo-bodytowedsystemcangreatlyincreasesthestabilityofthetowedsystem.

简介：Thenumericalsolutionofdamtoelineissolvedbasedonthedamdataandtopographicmapofdamlocated.ThedisplayofdamperspectiveisalsorealizedbyprogrammingofusingVC++andOpenGL.Theresearchresultsaboveprovidethefoundationofconstructiondesign,constructionloftingandinformationinquiry,whichavoidsthedrawbacksofonlyusingblueprintstodothesameworkinthepast.Themethodusedisusefulinpracticalengineering.

简介：Inthispaper,anumericalmodelof2Dweaklycompressiblesmoothedparticlehydrodynamics(WCSPH)isdevelopedtosimulatetheinteractionbetweenwavesandthinstructures.Anewcolordomainparticle(CDP)techniqueisproposedtoovercomedifficultiesofapplyingtheghostparticlemethodtothinstructuresindealingwithsolidboundaries.Thenewtechniquecandealwithzero-thicknessstructures.Toapplythisenforcingtechnique,thecomputationalfluiddomainisdividedintosubdomains,i.e.,boundarydomainsandinternaldomains.Acolorvalueisassignedtoeachparticle,andcontainstheinformationofthedomainsinwhichtheparticlebelongstoandtheparticlescaninteractwith.Aparticle,nearbyathinboundary,ispreventedfrominteractingwithparticles,whichshouldnotinteractwithontheothersideofthestructure.Itispossibletomodelthinstructures,orthestructureswiththethicknessnegligiblewiththistechnique.TheproposedWCSPHmoduleisvalidatedforastillwatertank,dividedbyathinplateatthemiddlesection,withdifferentwaterlevelsinthesubdomains,andisappliedtosimulatetheinteractionbetweenregularwavesandaperforatedverticalplate.Finally,thecomputationiscarriedoutforwavesandsubmergedtwin-horizontalplateinteraction.Itisshownthatthenumericalresultsagreewellwithexperimentaldataintermsofthepressuredistribution,pressuretimeseriesandwavetransmission.

简介：Thispaperaimsatinvestigationofthedynamicpropertiesofgravitycageexposedtowavesbyuseofanumericalmodel.Thenumericalmodelisdeveloped,basedonlumpedmassmethodtosetuptheequationsofmotionofthewholecage;meanwhilethesolutionsofequationsaresolvedbytheRunge-Kutta-Vernerfifth-orderandsixth-ordermethod.Physicalmodeltestshavebeencarriedouttoexaminethevalidityofthenumericalmodel.Theresultsbythenumericalsimulationagreewellwiththeexperimentaldata.

简介：Thegenerationandevolutionofturbulentspotsintheopen-channelflowaresimulatednumericallybyusingtheNavier-Stokesequations.Aneffectivenumericalmethodwithhighaccuracyandhighresolutionisdeveloped.Thefourth-ordertimesplittingmethodswithhighaccuracyisproposed.Three-dimensionalcouplingdifferencemethodsarepresentedforthespatialdiscretizationofthePoissonequationofpressureandHemholtzequationsofvelocity,therefore,thefourth-orderthree-dimensionalcouplingcentraldifferenceschemesareconstituted.Thefourth-orderexplicitupwind-biasedcompactdifferenceschemesaredesignedtoovercomethedifficultyforthegeneralhigher-ordercentraldifferenceschemewhichisinadaptableintheboundaryneighborhood.Theiterativealgorithmandoveralltimemarchingisusedtoenhanceefficiency.Themethodisappliedinthenumericalsimulationofturbulentspotsatvariouscomplexboundaryconditionsandflowdomains.Thegenerationandthedevelopingprocessofturbulentspotsaregiven,andthebasiccharacteristicsofturbulentspotsareshownbysimulatingtheevolutionofthewallpulseininclinedopen-channelflow.

简介：纸介绍一个词法模型和它的申请的发展给试验性的模型河。模型考虑隧道移植的关键进程，包括床变丑，河岸失败并且弄湿并且弄干。在拐弯的第二等的流动在侧面的沉积运输起一个重要作用，它进一步影响隧道移植。一个新公式被导出预言近床的第二等的流动速度，速度的大小在被连接到侧面的水水平坡度。因为仅仅非连贯的沉积在当前的学习被考虑，河岸失败基于休息的沉没角度的概念被建模。弄湿并且弄干的过程用一个存在方法被建模。在为各种各样的分泌物的数字模型预言和试验性的观察之间的比较被做了。模型预言隧道平面形状和代表性的形状与实验室观察通常同意很好，这被发现。情形分析也被执行在隧道迁居过程上调查第二等的流动的影响。它证明如果第二等的流动的效果被忽略，在侧面的方向的隧道尺寸将严重被低估。

简介：WeconsiderthenumericalsolutionfortheHelmholtzequationinR~2withmixedboundaryconditions.Thesolvabilityofthismixedboundaryvalueproblemisestab-lishedbytheboundaryintegralequationmethod.BasedontheGreenformula,weexpressthesolutionintermsoftheboundarydata.Thekeytothenumericalreal-izationofthismethodisthecomputationofweaklysingularintegrals.Numericalperformancesshowthevalidityandfeasibilityofourmethod.Thenumericalschemesproposedinthispaperhavebeenappliedintherealizationofprobemethodforinversescatteringproblems.

简介：Windsontheeartharecommonlystrongenoughtoerodetransportanddepositsediment.Themodesofsandtransportbythewindaregreatlydifferentfromthosebywaterflow.Ontheotherhandwind-blownsandsareofamaterialcirculationprocessoftheearthsurface.Theyaffectwind-sandtransportfluxandsandejectionofaflux,thedamageofgrainsformedcannotbeneglectedinengineering.Becauseofthecomplexityofwindblownsandfluxsystem,theunderstandingofitsbasicmechanicsisnotyetclear.Thekeyforcesinsandsalutationmainlyincludes:thevalidgravity,airdragforce'Magnusforce'Saffmanforce'Bassetforce'additionalqualityforceandscatterforceamonggrains.Themostimportantforceinsandsalutationistheairdragforce.Computationofthesinglespheredragcoefficientanddoublespheresdragcoefficientispresentedforthedistancebetweentwospheresbeingsmallerthantwelvetimesofthespherediameterandthespheresbeingatdifferentangularpositions.Theflowinterferenceoftwosphereswasinvestigatedforthedistances=0.08dto12d,angularpositionθ=0to360andReynoldsnumber1≤Re≤1000.

简介：Inthispaper,thefrontogenesisforcedbydustradiativeheatingandtheradiativeeffectsofanisolatedduststorrnonafrontalcirculationsystemareexaminedbymeansoftwo-andthree-dimensionalnumericalmodels.Resultsindicatethatasaduststormbreaksout,frontogenesisiscausedinbydustradiativeheatingintheloweratmosphere.Amarkedisentropicpotentialtemperaturelayerisformedinthemiddletroposphere.Thelow-levelconvergenceoccursalongthedirectionofthefrontmovement.Atnight,dustradiativecoolingresultsinfrontolysisintheloweratmosphere.Anobviousverticalcirculationisforcedbyradiativeheatingofanisolatedduststormalongthedirectionofthepre-vailingwind.Itisstrongeratday,weakerandreverseatnight.Theresponseofthehorizontalwindfieldtodustradiativeforcingisdifferentatdifferentlevels.

简介：AccordingtoLorenz,chaoticdynamicsystemshavesensitivedependenceoninitialconditions(SDIC),i.e.,thebutterfly-effect:atinydifferenceoninitialconditionsmightleadtohugedifferenceofcomputer-generatedsimulationsafteralongtime.Thus,computer-generatedchaoticresultsgivenbytraditionalalgorithmsindoubleprecisionareakindofmixtureof'true'(convergent)solutionandnumericalnoisesatthesamelevel.Today,thisdefectcanbeovercomebymeansofthe'cleannumericalsimulation'(CNS)withnegligiblenumericalnoisesinalongenoughintervaloftime.TheCNSisbasedontheTaylorseriesmethodathighenoughorderanddatainthemultipleprecisionwithlargeenoughnumberofdigits,plusaconvergencecheckusinganadditionalsimulationwithevensmallernumericalnoises.Intheory,convergent(reliable)chaoticsolutionscanbeobtainedinanarbitrarylong(butfinite)intervaloftimebymeansoftheCNS.TheCNScanreducenumericalnoisestosuchalevelevenmuchsmallerthanmicro-leveluncertaintyofphysicalquantitiesthatpropagationofthesephysicalmicro-leveluncertaintiescanbepreciselyinvestigated.Inthispaper,webrieflyintroducethebasicideasoftheCNS,anditsapplicationsinlong-termreliablesimulationsofLorenzequation,three-bodyproblemandRayleigh-Bénardturbulentflows.UsingtheCNS,itisfoundthatachaoticthree-bodysystemwithsymmetrymightdisruptwithoutanyexternaldisturbance,say,itssymmetry-breakingandsystem-disruptionare'self-excited',i.e.,out-of-nothing.Inaddition,bymeansoftheCNS,wecanprovidearigoroustheoreticalevidencethatthemicro-levelthermalfluctuationistheoriginofmacroscopicrandomnessofturbulentflows.Naturally,muchmoreprecisethantraditionalalgorithmsindoubleprecision,theCNScanprovideusanewwaytomoreaccuratelyinvestigatechaoticdynamicsystems.

简介：Experimentalrevelationofsuperbluntingalongplanestrainpredominantcracktipsegmentisre-portedhereformodifiedpolyproplene.Aselucidatedbyaheuristicmodelofprogressivecircumferentialcold-draw,theformationofsuperbluntingcracktipdependscriticallyontheratiobetweenthecold-drawprop-agationspeedandtheloadingspeed,andcontributessignificantlytothematerialtoughening,especiallyfortheimprovementinimpacttoughness.Detailednumericalcalculationsareconductedbasedonahyperelastic-viscoplasticandanisotropicdamageconstitutivemodelatfinitedeformation.Thesimulatedresultsrecapitulatetheessentialfeaturesofcracktipsuperblunting.

简介：InthispaperTVDexplicitschemesdevelopedrecentlyinCFDareusedtosimulatefivemodelsofboresduetodam-break.Numericalexperimentsarepresentedtodemonstratethattheyachievehighresolutionandgeneratenospuriousoscillationsandtoshowtheversatilityoftheschemes.

简介：Forthesimulationofthenonlinearwavepropagationincoastalareaswithcomplexboundaries,anumericalmodelisdevelopedincurvilinearcoordinates.Inthemodel,theBoussinesq-typeequationsincludingthedissipationtermsareemployedasthegoverningequations.Inthepresentmodel,thedependentvariablesofthetransformedequationsarethefreesurfaceelevationandtheutilityvelocityvariables,insteadoftheusualprimitivevelocityvariables.TheintroductionofutilityvelocityvariableswhicharetheproductsofthecontravariantcomponentsofthevelocityvectorandtheJacobimatrixcanmakethetransformedequationsrelativelyconcise,thetreatmentoflateralboundaryconditionseasierandthedevelopmentoftheprogramsimpler.Thepredictor-correctormethodandfive-pointfinite-differenceschemeareemployedtodiscretizethetimederivativesandthespatialones,respectively.Thenumericalmodelistestedforthreecases.Itisfoundthatthenumericalresultsareingoodagreementwiththeanalyticalresultsandexperimentaldata.

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简介：在Bohai海湾的热带以外的暴风雨巨浪和淹没的一个二维的数字模型基于不稳定的流动海军司烧方程被造。模型包括了二节，一个人为暴风雨巨浪的模拟为在沿海的区域的暴风雨巨浪淹没的模拟的潮汐的水平和其它。当模仿暴风雨时，澎湃潮汐的水平，轮流出现的方向含蓄(ADI)方法被用于驱散并且解决2D暴风雨巨浪方程。在暴风雨巨浪淹没的模拟，2D不稳定的流动方程被驱散并且解决了使用有限体积方法(FVM)的无结构的格子。淹没和暴风雨巨浪的过程的Acoupling计算模式潮汐的水平变化被建议，当模仿并且预报暴风雨巨浪的过程时，因此，暴风雨巨浪淹没过程和区域能被计算潮汐的安装。而且，在Bohai海湾的热带以外的暴风雨巨浪和淹没用这个数字模型被模仿。模拟结果在对测量数据的好同意，它证明这个数字模型提供在Bohai海湾模仿并且预报暴风雨巨浪和淹没的一个新方法。

简介：Basedonthesimulationsofthehilly-landtopographicparameters,i.e.,averageorientationandslope,andtopographicscreenangle,atheoreticalmodelisdetailedtogreaterextentforglobalradiationoverhillycountriesintermsoftheexperimentaldata.Threemainaspectsareexamined:themodelconstruction;numericalrunwiththemodelparameters;discussionofsimulationsobtainedlocallyinthemodelrunforthesouthernDabieMountains.Resultsshowthatthesignificanteffectofthetopographyonglobalradiation.Thepresentmodelappliesinprincipletothenumericalsimulationofglobalradiationforanyformoftopographyofvariousregions.

简介：SedimentationofparticlesininclinedandverticalvesselsisnumericallysimulatedbytheEuleriantwo-fluidmodel.Thenumericalresultsshowaninterestingphenomenonwithtwocirculationvortexesinaverticalvesselbutoneintheinclinedvessel.Sensitivitytestsindicatethattheboundarylayereffectisthekeytoinducethisphenomenon.Anumericalmethodbasedon2Dunstructuredmeshesispresentedtosolvethehard-spherediscreteparticlemodel.Severalapplicationsshowthenumericalmethodhasagoodperformancetosimulatedenseparticulateflowsinirregulardomainswithoutregardtoelementtypesofthemesh.

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简介：AftertheprogressivecollapseofRonanPointapartmentinUKin1968,intensiveresearchefforthadbeenspentondevelopingguidelinesfordesignofneworstrengtheningtheexistingstructurestopreventprogressivecollapse.However,onlyveryfewbuildingdesigncodesprovidesomerathergeneralguidance,nodetaileddesignrequirementisgiven.ProgressivecollapseoftheAlfredP.MurrahFederalbuildinginOklahomaCityandtheWorldTradeCentre(WTC)sparkedagaintremendousresearchinterestonprogressivecollapseofstructures.Recently,USDepartmentofDefence(DoD)andUSGeneralServiceAdministration(GSA)issuedguidelinesforstructureprogressivecollapseanalysis.Thesetwoguidelinesaremostcommonlyused,buttheiraccuracyisnotknown.Thispaperpresentsnumericalanalysisofprogressivecollapseofanexampleframestructuretoblastloads.TheDoDandGSAproceduresarealsousedtoanalysethesameexamplestructure.Numericalresultsarecomparedanddiscussed.Theaccuracyandtheapplicabilityofthetwodesignguidelinesareevaluated.