简介：Asimulationiscarriedoutforthepressurefluctuationdrivenbythewaterhammer,basedonajointuseoftheonedimensionalmethodofcharacteristics(MOC)andthethree-dimensionalfinitevolumemethod(FVM).Thethree-dimensionalvisualizationofthecavitationinducedbythewaterhammerisimplemented,andthetemporalandspatialanalysesofextremeregionsaremade.Apracticalcaseofthewaterhammer,withtheminimumboundarypressurehigherthanthesaturatedvaporpressurecondition,issimulated.Thesimulationpredictionthatthecavitationwouldoccurinthefrontofthegasketcouldservesomeguidelinefortheoptimizationofindustrialdesigns.

简介：ThisarticlepresentstheresultsofanumericalsimulationonthevortexinducedvibrationofvariousfinnedcylindersatlowReynoldsnumber.Thenon-dimensional,incompressibleNavier-Stokesequationsandcontinuityequationwereadoptedtosimulatethefluidaroundthecylinder.Thecylinder(withorwithoutfins)influidflowwasapproximatedasamass-springsystem.Thefluid-bodyinteractionofthecylinderwithfinsanduniformflowwasnumericallysimulatedbyapplyingthedisplacementandstressiterativecomputationonthefluid-bodyinterfaces.Bothvortexstructuresandresponseamplitudesofcylinderswithvariousarrangementsoffinswereanalyzedanddiscussed.TheremarkabledecreaseofresponseamplitudefortheadditionsofTriangle60finsandQuadrangle45finswasfoundtobecomparablewiththatofbarecylinder.However,theadditionsofTriangle00finsandQuadrangle00finsenhancetheresponseamplitudegreatly.Despitetheassumptionoftwo-dimensionallaminarflow,thepresentstudycangiveagoodinsightintothephenomenaofcylinderswithvariousarrangementsoffins.

简介：Thisarticleanalyzestheverticalstructureoftheonshorecurrentincludingthewave-inducedcurrentbyanequationdevelopedfortheradiationstressagainstwaterdepth.AcoupledmodelCOHERENS-SEDisadoptedtocalculatethewave,tidalcurrent,wave-inducedcurrentandsedimentsimultaneously.ByapplyingthenewmodeltoYangpuBay,itsreliabilityisverified.Thenanidealcoastaldomainisdefinedtosimulatethenearshorecurrentandwavesetupwithnormalincidentwaves.Thenumericalandexperimentalresultsfortheverticalstructureshowtwoundertows,alsoavisiblesetupinthesurfzone.Itdemonstratestheimportanceoftheradiationstressinwave-inducedcurrentsandmeanwaterlevels(set-up/down).

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简介：这份报纸调查大小Mw=9.30作为马尼拉沟在华南海(SCS)正在成为最危险的海啸来源区域之一。用方程建模的非线性的浅水，表面举起，到达时间，最大的波浪振幅的空间分布和速度分发的时间系列被介绍。波浪和水流的特征被分析。数字结果显示波浪散布在的海啸的精力的那个大多数中央并且SCS的北方部分。近海在SCS附近的区域将被地震在马尼拉subduction地区产生的海啸水流显著地影响。广东省，海南岛，和台湾岛附近的最大的波浪振幅在海岸附近在测量地点的多数超过4m和速度超过2m/s。有高分辨率的嵌套的格子被用来在海南岛，台湾岛，和Lingding海湾上学习海啸的影响。有高危险风险的区域由于强壮的水流被识别。最后，在SCS的一个快海啸警告方法被开发并且讨论，它能在5min提供海啸警告信息。

简介：Flow-inducedvibrationoftwocircularcylindersintandemarrangementelasticallymountedwithamass-spring-dampingsystemwasstudiedbysolvingtheprimitivevariableNavier-StokesequationsincorporatingtheArbitraryLagrangian-Eulerian(ALE)method.Theconvectiontermanddissipationtermwerediscretizedusingthethird-orderupwindcompactschemeandthefourth-ordercentralcompactscheme,respectively.Thetypicalspacingbetweenthecylindersis4diameters,whichisclosetothecriticalvalue.Thedynamicresponseofthevibrationsontwocylinderswithtwo-degree-of-freedommotionisdifferentfromthatofanisolatedcylinder,andalsodifferentfromthatofacylindervibratinginthewakeofafixedupstreamone.Differentflowpatternswerefoundinthewake,andprovedtoberelevanttothediscontinuitiesobservedintheresponseoftheoscillatorycylinders.

简介：Thetransientgravitywavesduetoanimpulsivesourceinatwo-layerfluidsystemareinvestigatedanalytically.Thefluidisassumedtobeinviscidandincompressible.Thedensityofeachofthetwolayersisconstant.Fivedifferentboundaryconditionsareconsidered.Thedepthofeachofthetwolayersisinfiniteorfinite.Theupperfluidoffinitedepthiscoveredbyarigidlidorafreesurface.Basedontheassumptionofsmall-amplitudewaves,alinearsystemisestablished.Theintegralsolutionsforthefree-surfaceandinterfacialwavesareobtainedbymeansoftheFourier-Laplacetransform.Thecorrespondingasymptoticrepresentationsarederivedforlargetimewithafixeddistance-to-timeratiobytheStokesandScorermethodsofstationaryphase.Theanalyticalsolutionsshowthattherearetwodifferentmodes,namelythefree-surfaceandinterfacialwavemodes.Thewaveprofilesobserveddependontherelationbetweenthedistance-to-timeratioandthemaximalgroupvelocitiesandonthelimitingvaluesofthesecondderivativesofthefrequenciesaswell.

简介：Theaimofthisexperimentalstudyistoinvestigatetheeffectsofhydraulicparametersontheformationofair-entrainingvorticesathorizontalintakestructureswithoutapproachflowinducedcirculation.Sixintakepipesofdifferentdiametersweretestedinthestudy.Theintakepipetobetestedwashorizontallymountedtothefrontsideofalargereservoirandthenforawiderangeofdischargesexperimentswereconductedandcriticalsubmergencesweredetectedwithadjustableapproachchannelsidewalls.Empiricalequationswerederivedforthedimensionlesscriticalsubmergenceasafunctionoftherelevantdimensionlessparameters.Availabledataisalsocheckedforthepossiblescaleeffect.Then,theseobtainedequationswerecomparedwiththesimilaronesintheliteraturewhichshowedaquitegoodagreement.

简介：ANonlinearFluidDamping(NFD)intheformofthesquare-velocityisappliedintheresponseanalysisofVortex-InducedVibrations(VIV).Itsnonlinearhydrodynamiceffectsonthecoupledwakeandstructureoscillatorsareinvestigated.AcomparisonbetweenthecoupledsystemswiththelinearandnonlinearfluiddampingsandexperimentsshowsthattheNFDmodelcanwelldescriberesponsecharacteristics,suchastheamplificationofbodydisplacementatlock-inandfrequencylock-in,bothathighandlowmassratios.Particularly,thepredictedpeakamplitudeofthebodyintheGriffinplotisingoodagreementwithexperimentaldataandempiricalequation,indicatingthesignificanteffectoftheNFDonthestructuremotion.

简介：ACFDsimulationisperformedforaparticle-ladenplanarjetflow.TheReynoldsnumberis8300,andtheinitialparticlediameteris1μm.LargeEddySimulation(LES)isemployedtocalculatetheflowfield,andtheTaylor-seriesexpansionmomentmethod(TEMOM)isadoptedtodealwiththebalanceequationofparticlecoagulationandbreakage.Theshear-inducedcoagulationkernel,power-lawbreakagekernelandsymmetricfragmentdistributionfunctionareinvolved.Thepredictionofthedistributionofthemeanstreamwisevelocityofthejetisingoodagreementwithexperimentaldata.Theevolutionofparticlenumberconcentration,volumeconcentration,polydispersity,particlediameterandstandardgeometricdeviationisdiscussedindetail.Theresultsshowthatasthejettravelsdownstream,theparticlenumberconcentrationandvolumeconcentrationdecrease,whiletheirspansbecomewider.Thepolydispersityandparticlediameterareverylargeintheshearlayersattheupstreamandinthecoreofvortexstructuresatthedownstream.Theparticlestandardgeometricdeviationchangeswithintherangeof1.32≤σg≤1.96,andincreasessharplyintheshearlayers.Allvariablesapproachthesteady-stateastimeprogresses.