简介：WithrespecttothecrestspillwaywithlargeunitdischargeandlowFroudenumber,thehydraulicsoftheslit-typeenergydissipaterattheoutletshouldbenoticedduetothecomplicatedflowregimes.Inthepresentpaper,someissuesabouthydrauliccharacteristicswereexperimentallyinvestigatedbymeansoffiveslit-typeoutletsandfourtetrahedrons,includingtheflowchoking,impacttoriverbanksandjettrajectory.Themainfindingsareasfollows.ThecriticalFroudenumberfortheflowchokingdecreaseswithincreasingoutletwidthoftheslit-typeenergydissipater.IftheflowFroudenumberisexpressedbytheparametersjustbeforethisenergydissipater,thetetrahedronplacedinsidethesidewalloftheoutletcouldefficientlyavoidtheflowimpacttotheriverbankofsameside,andcomparedwiththejettrajectoryoftheslit-typeenergydissipater,theoutletwithtetrahedronhasdifferenttrajectorytrend,i.e.,thedistanceofthejettrajectorydecreaseswiththeincreaseofthewaterheadduetospecialformoftheoutlettetrahedron.

简介：在这篇论文，在在低严肃下面的一辆矩形的坦克的液体sloshing的动力学被调查。基本频率和液体的sloshing的速度潜力被Fourier系列的扩大获得。力量的特征和液体作用于的时刻一辆矩形的坦克被分析。液体的sloshing的相等的机械模型ofspring-vibrator-damper与机械相等的原则被建立，数字结果被给。数字结果证明相等的sloshing团随严肃的增加增加，并且基本频率和相等的sloshing团随液体深度的增加增加。

简介：TheUSM-θmodelofpowerlawfluidfordensetwo-phaseturbulentflowwasdeveloped,whichcombinestheunifiedsecond-ordermomentmodelfortwo-phaseturbulencewiththeparticlekinetictheoryfortheinter-particlecollision.Thismodelwasusedtosimulatetheturbulentflowofpowerlawfluidsingle-phaseinpipe.ItisshownthattheUSM?θmodelhasbetterpredictionresultthanthekf?εf?kp?εp?θmodel.TheUSM?θmodelwasthenusedtosimulatethedensetwo-phaseturbulentupflowofpowerlawfluidwithparticles.Withtheincreaseoftheflowexponent,thevelocitiesofpowerlawfluidandparticlesincreasenearthepipecentre.Comparisonbetweenthetwo-phaseflowofpowerlawfluid-particleandofliquid-particleindicatesthattheaxialfluctuationvelocityoffluidphaseandparticlephaseinliquid-particletwo-phaseflowissmallerthanthatinthepowerlawfluidtwo-phaseflow,butthetwo-phasevelocitiesofpowerlawfluid-particleandliquid-particleareclosetoeachother.

简介：Ahigh-orderfinitedifferencePadéschemealsocalledcompactschemeforsolvingKorteweg-deVries(KdV)equations,whichpreserveenergyandmassconservations,wasdevelopedinthispaper.Thisstructure-preservingalgorithmhasbeenwidelyappliedintheseyearsforitsadvantageofmaintainingtheinheritedproperties.Forspatialdiscretization,theauthorsobtainedanimplicitcompactschemebywhichspatialderivativetermsmaybeapproximatedthroughcombiningafewknots.Bysomenumericalexamplesincludingpropagationofsinglesolitonandinteractionoftwosolitons,theschemeisprovedtobeeffective.

简介：Existingfarfieldexpressionsofsecondorderpotentialsarebynomeanscomplete.Hencetherehasbeennoexactfarfieldexpressionofsecondorderpotentials.InthispaperthefarfieldexpressionforΦd（2）ispurposelyavoidedindeducingtheformulaeofsecondorderforcesandaseriesoffunctionsΦdRnareused.Thefarfieldexpressionofisgiven,whichfor（x,U,z）∈Σ,φdRn（2）φd（2）.Usingthesepropertiesformulaeforcalculatingsecondorderdiffractionforcesareobtained.Tocalculatetheintegral∫∫1/gfΨdsitisdividedintotwoparts.Oneistheintegraloverafinitedomainandthefunctionundertheintegraliscontinuous,sotheusualapproximateintegrationformulaemaybeused.Theotheristheintegraloveraninfinitedomain.Usingthefarfieldexpressionoffirstorderpotentials,formulaeforcalculatingtheintegraltomeetgivenaccuraciesaregiven.Themooringforceinsurgedirectionisusedforcomparisonbetweennumericalpredictionsandexperimentalmeasurements.Thepredictedresultsarecheckedagainstthemeasuredvalueinaspeciallydesignedtest.Inthelowfrequencydomainofinterest,themooringforcesinsurge,forcalculatedandexperimentalspectraareingoodconsistencysolongasthedampingcoefficientsischoosenappropriately.

简介：

简介：Basedonthenon-Darcyflowcharacteristicsofsurfactantfloodinginthelowpermeabilityoilfield,consideringthechangesofthresholdpressureandinfluenceofsurfactantonconvection,diffusion,adsorptionandretention,amathematicalmodelisestablishedforathree-dimensional,two-phase,three-componentsurfactantflooding.Anewtreatmentforthechangesofthresholdpressureandanovelcorrectionmethodfortherelativepermeabilitycurveintheprocessofsurfactantfloodingarederived,whichenhancesthematchingdegreebetweenthemathematicalmodelandfieldpractice.ThemathematicalmodelwasusedtoperformthenumericalsimulationstudyforapilottestofsurfactantfloodinginChao45BlockofDaqingOilfield,aproperinjectionplanwasoptimized.Aftertheoptimizedplanwascarriedoutinoilfield,thedesirableeffects,likepressure-reducing,injectionrateincrease,andtheincreaseofoilrecovery,wereachieved.Theaverageoilincreaseforsinglewellreaches37%,theratioofcosttorevenueisabove1:4,sotheeconomiceffectofscaleispromising.

简介：Thedynamicsofliquidsloshinginasphericaltankwithspacerunderlowgravitywasinvestigated.Byextendingthecharacteristicfunctions,thefrequenciesofliquidfree-sloshing,reactionforceandmomentsonthewalloftankwereobtained.Bymechanicalequivalentprinciple,theequivalentmodelsofspring-vibrator-damperofliquidsloshingweregiven.Thenumericalresultsobtainedshowwhenaspacerisinsertedinthetank,thesloshingfrequencyofliquidandthesloshingmassofliquidwilldecrease.

简介：Theboundaryelementmethod(BEM)isamainmethodforanalyzingtheinteractionsbetweenthewavesandthemarinestructures.AswiththeBEM,asetoflinearequationsaregeneratedwithafullmatrix,therequiredcalculationsandstorageincreaserapidlywiththeincreaseofthestructurescale.Thus,anacceleratedmethodwithalowstorageisdesirableforthewaveinteractionwithaverylargestructure.AsystematicreviewisgiveninthispaperfortheBEMforsolvingtheproblemofthewaveinteractionwithalargescalestructure.VariousintegralequationsarederivedbasedondifferentGreenfunctions,theadvantagesanddisadvantagesofdifferentdiscretizationschemesoftheintegralequationsbytheconstantpanels,thehigherorderelements,andthesplinefunctionsarediscussed.Forthehigherorderelementdiscretizationmethod,thespecialconcernsaregiventothenumericalcalculationsofthesingle-layerpotential,thedoublelayerpotentialandthesolidanglecoefficients.Foralargescalecomputationproblemsuchasthewaveinteractionwithaverylargestructureoralargenumberofbodies,theBEMswiththeFMMandpFFTaccelerationsarediscussed,respectively,includingtheprinciplesoftheFMMandthepFFT,andtheirimplementationsinvariousintegralequationswithdifferentGreenfunctions.Finally,somepotentialapplicationsoftheaccelerationmethodsforproblemswithlargescalecomputationsintheoceanandcoastalengineeringareintroduced.

简介：Avariablecoefficient,rotation-modifiedextendedKortweg-deVries(vReKdV)modelisappliedtothestudyoftheSouthChinaSea(SCS),withfocusontheeffectsofthehigh-order(cubic)nonlinearityandtherotationonthedisintegrationprocessoflarge-amplitude(170m)InternalSolitaryWaves(ISWs)andthesemi-diurnalinternaltidepropagatingfromthedeepbasinstationtotheslopeandshelfregionsinacontinuouslystratifiedsystem.Thenumericalsolutionsshowthatthehigh-ordernonlinearitysigni-ficantlyaffectsthewaveprofilebyincreasingthewaveamplitudeandthephasespeedinthesimulatedarea.ItisshownthattheinitialKdV-typeISWwilldecayfasterwhentherotationdispersionisconsidered,howeverthewaveprofiledoesnotchangesignificantlyandtherotationeffectisnotimportant.Thesimulationsofthesemi-diurnalinternaltideindicatethatthephaseofthewaveprofileisshiftedearlierwhentherotationeffectisincluded.Asolitarywavepacketemergesontheshelf,andthewavespeedisalsogreaterwhenconsideringtherotationdispersion.Inaddition,theeffectsofthebackgroundcurrentsarediscussedfurtherinthispaper.ItisfoundthatthebackgroundcurrentsgenerallychangethemagnitudeandoccasionallychangethesignofthenonlinearcoefficientsinthenorthernSCS.

简介：Thedynamiccharacteristicsofliquidsloshinginatransverselyvibratingsphericaltankwithspacerunderlowgravitywereinvestigated.Byexpandingthecharacteristicfunctions,thefrequenciesandvelocitypotentialsofliquidfree-sloshingwereobtained.Thedynamicequationsandboundaryconditionsofliquidsloshinginthetraversevibrationalsphericaltankwithspacerunderlowgravitywerederived.Bymodifyingthevelocitypotentialsofliquidfree-sloshing,thevelocitypotentialsofliquidsloshinginthetraversevibratingsphericaltankwithaspacerwereobtained.Furthermore,theforcesandthemomentsactingontankwallweregiven.Thenumericalresultsshowwhenaspacerisinsertedinthetank,thesloshingfrequenciesofliquidandtheforcesactingontankwallwilldecrease,butthemomentofforcetothecentreofthetankwhichiscausedbytheforceofliquidactingonthespacerwilloccur.

简介：Undertheconditionoflowgravitythecharacteristicsofliquidforcedsloshinginaturningsphericaltankwithaspacerwereinvestigated.Thestaticshapeoftheliquidsurfacewasanalyzed.Byexpandingthecharacteristicfunctions,thefrequenciesandvelocitypotentialofliquidfree-sloshingwerederived.Thegoverningequationsandboundaryconditionsfortheforcedsloshingofliquidunderthetankturningwereestablished.Thetransverseforceofliquidactingonthetankandthemomentofforcetothecentreofthetankwhichiscausedbytheforceofliquidactingonthespacerweregiven.Numericalresultswerecomparedwiththeonesofthesphericaltankwithoutaspacer.Theresultsshowthatwhenaspacerisinsertedinthetank,thesloshingfrequencyofliquidandthetransverseforceofliquidactingonthetankwilldecrease,butthemomentofforcetothecentreofthetankwhichiscausedbytheforceofliquidactingonthespacerwilloccur.

简介：

简介：Twonear-fieldmethods,namelytheintegralmethodanddifferentialmethod,werepresentedforgivingsecond-ordermeandriftforcesandmomentsbetweentwofixedsubmergedbodiesinregularwaves.Fortheintegralmethod,withaseriesofmathematicalmanipulations,second-orderdriftforcesandmomentscouldbeeasilyexpressedbydistributedsourceswhichcouldbecalculatedbysourcedistributiontechniqueswiththeassumptionthattheamplitudeofshipmotionsaresmallonthebasisofthelinear3Dfrequencytheory.Forthedifferentialmethod,driftforcesandmomentscouldbeexpressedbythederivativeofvelocitypotentialwithrespecttospacecoordinate.Becausetwobodieswouldbehaveasasinglebodywhiletheclearanceisverylarge,thenumericalresultsofonesphereinsuchcaseweregivenandcomparedwithanalyticalresultsofasinglespherewhichdoesnotinvolvetheeffectoffreesurface.Whensubmergeddepthbecomesenoughlarge,agoodagreementcanbereached.Thentheintegralmethodwasusedtopredictthesecond-orderdriftforcesandmomentsoftwosubmergedspheresandspheroidswithasmalllateralseparationdistanceinwavescomparedwiththenumericalresultsobtainedbythedifferentialmethodandtheyagreewell.Bycomparison,itindicatestheinteractioneffectsbetweentwosubmergedbodieshaveaprofoundinfluenceonthedriftforcesandmoments.Inthispaper,theforwardspeedeffectonsubmergedsphereswasalsoconsidered.

简介：Flowdistributionheadersplayamajorroleinheatexchangers.Theselectionofheaderdiameter,branchpipediameter,branchpipespacingetc.isbasedonthedesigner'sexperienceandgeneralguidelines.Theproperselectionoftheheaderdimensionswillyielduniformflowdistributioninheatexchangers,whichinturnwillenhancetheheatexchangerefficiency.Inthiswork,theflowdistributioninbranchpipesandthepressurevariationacrossthebranchpipesinlaminarandlowturbulenceregionisstudiedwithtwomodelsoftheinletdividingheaders.Whenthenumericalanalysishasbeenapplied,itsinabilitytopredictthenoflowconditionthroughthebranchpipesisrevealed.Theresultsarepresentedintheformofflowrateratiothroughbranchpipesandnondimensionalcoefficientsacrossbranchpipeswhichareusefultoapplytheexistingmathematicalmodelsforthepresentexperimentalsetup.

简介：Inthisarticle,thelowpressureaxialflowfanwithcircumferentialskewedrotorblade,includingtheradialblade,theforward-skewedbladeandthebackward-skewedblade,wasstudiedwithexperimentalmethods.Theaerodynamicperformanceoftherotorswasmeasured.Atthedesignconditionatoutletoftherotors,detailedflowmeasurementswereperformedwithafive-holeprobeandaHot-WireAnemometer(HWA).Theresultsshowthatcomparedtotheradialrotor,theforward-skewedrotordemonstratesawiderStableOperatingRange(SOR),isabletoreducethetotalpressurelossinthehubregionandmakemainloadingofbladeaccumulatinginthemid-spanregion.Thereisawiderwakeintheuppermid-spanregionoftheforward-skewedrotor.Comparedtotheradialrotor,inthebackward-skewedrotorthereishighertotalpressurelossnearthehubandshroudregionsandlowerlossinthemid-spanregion.Inaddition,thevelocitydeficitinthewakeisloweratmid-spanofthebackward-skewedrotorthantheforward-skewedrotor.

简介：Duringthedevelopmentoflowpermeabilityreservoirs.theinteractionbetweenfluidflowandrock-massdeformationisobvious.Onthebasisoffluidmechanicsinporousmediaandelasto-plastictheory.theauthorpresentsanequivalentcontinuummodeltosimulatefluidflowinfracturedlow-permeabilityoilreservoircoupledwithgeo-stress.Themodelnotonlyreflectstheporositychangeofmatrix,butalsothepermeabilitychangeduetotheopeningandclosingoffracture.Byanalyzingofsimulationresults,thechangesinporosityandpermeabilityandtheireffectonoildevelopmentarestudied.

简介：Inthepresentpaper,two-andthree-dimensionalvelocitypotentialsgeneratedbypulsatingpressuredistributionsofinfiniteextentonthefreesurfaceofinfinite-depthwatersarestrictlyderivedbasedonspecialcasesofconcentratedpulsatingpressure.Thefar-fieldasymptoticbehaviourofthepotentialsandtheradiationconditionstobesatisfiedbythemarediscussed.Itisprovedinageneralsensethatthepotentialsshouldbecomposedofaforcedwavecomponent,afreewavecomponentandalocaldisturbancecomponent.Theradiationconditionoftheforcedwavecomponentshouldcorrespondtothefar-fieldasymptoticbehaviourofthepressuredistribution,Hence,theformulationofradiationconditionsforthesecond-orderdiffractionpotentialshastheoreticallybecomeclear,Theradiationconditionsfortwo-andthree-dimensionalproblemsareexplicitlygiveninthepaper.