简介：Atypeofportwithamovablecoverisdesignedtoincreaseinitialdilutionandpreventseawaterandsedimentsfromintrudingintooutfallsystems.Horizontalradialjetspro-ducedbythistypeofportinacurrentareinvestigatedexperimentallyandtheoretically.TheanalysisbasedonReynolds’equationsandself-similarityhypothesisshowsthatthemaximumve-locityofradialjetsdecayswithr-1.5.Therelationshipsbetweenthewidth,thickness,averagedi-lutionofasubmergedwastefieldalongflow,andtheparametersoftheport,jetandambientareestablishedquantitativelyandverifiedbyexperiments.Itisdemonstratedthatthedilutionofhorizontalradialjetsismuchhigherthanthatofverticalroundjetsandthesurfaceboilpointoftheformerismuchmoredistantthanthatofthelatter.

简介：AnewtypeBoussinesqmodelisproposedandappliedforwavepropagationinawaveflumeofuniformdepthandoverasubmergedbarwithcurrentpresentorabsent,respectively.Firstly,forthepropagationofmonochromaticincidentwavewithcurrentabsent,theBoussinesqmodelistestedinitscompleteform,andinaformwithouttheintroductionofutilityvelocityvariables.Itisvalidatedthattheintroductionofutilityvelocityvariablescanimprovethecharacteristicsofvelocityfield,dispersionandnonlinearity.BothversionsoftheBoussinesqmodelsareofhigheraccuracythanthefully-nonlinearfourth-ordermodel,whichisoneofthebestformsamongtheexistingtraditionalBoussinesqmodelsthatdonotincorporatebreakingmechanisminonedimension.Secondly,theBoussinesqmodelinitscompleteformisappliedtosimulatingthepropagationofbichromaticincidentwaveswithcurrentpresentorabsent,respectively,andthemodeledresultsarecomparedtotheanalyticalonesortheexperimentalones.Themodeledresultsarereasonableinthecaseofinputtingbichromaticincidentwaveswiththestrongopposingcurrentpresent.

简介：Inthispaperthefiniteelementmethodisusedtosolvethetwo-dimensionalgradi-entcurrentproblem,Thesolutionisobtainedbytwo-stepexplicitmethod.ItisverifiedwithgoodagreementbythefielddataofferedbyXiamenE.P.A.,Fujian,P.R.C.Theauthorsrec-ommendthattheproposedmethodissuitablefortheanalysisandcomputationoflongwavesofepeiricseaattheseawardfirth.

简介：ThepresentworkadoptstheCOHERENS-SWANmodeldevelopedbythefirstauthorthroughcouplingthree-dimensionalhydrodynamicmodel(COHERENS)andthird-generationwavemodel(SWAN).InsidetheCOHERENS-SWAN,theSWANisregardedasasubroutineandthetime-andspace-varyingcurrentvelocityandsurfaceelevationareobtainedfromtheCOHERENS.Wave-enhancedbottomshearstress,waveinducedsurfacemixinglengthandwavedependentsurfacedragcoefficienthavebeenintroducedintotheCOHERENS.Secondly,aswave-enhancedbottomshearstress('bottomshearstress'describedasBSSsometimesinthisarticle)isconcerned,amodifiedbottomshearstressGrantandMadsenmodelwhichintroducesrandomwavefieldisgivenandintroducedtoCOHERENS-SWAN.COHERENS-SWANisalsoadoptedtosimulatethree-dimensionalflowintheYellowRiverDeltawithwave-currentco-existing.Fournumericalexperimentsweregiventostudytheeffectsofwave-currentinteractiononenhancingbottomshearstress.Thesimulatedcurrentvelocities,waveheightandwaveperiodmatchwellwithfieldmeasurementdata.Thesimulatedsignificantwaveheightandwaveperiodforthecasewithconsideringtheeffectsofcurrentcangivebetteragreementwithmeasurementdatathanthecasewithoutinvolvingtheeffectsofcurrent.Theintroductionofrandomwavegenerateslowerthebottomshearstressthanthecasewithoutintroducingit.Thereareobviousdifferencesbetweenbottomshearstressoftwowayinteractionandonewayinteraction.VelocityfieldobtainedbytheCOHERENS-SWANisreasonableaccordingtopreviousstudiesandmeasurements.

简介：Duringthedesignandconstructionofthedeepwateroffshorebasin,itscurrentgenerationsystemisconsideredtobeoneofthekeytechnologies.Inthisarticle,thestate-of-the-artdeepwateroffshorebasinatShanghaiJiaotongUniversitywasexaminedasacasestudy.Different3-Dnumericalmodelsofthecurrentgenerationsystemweredevelopedandcalculated.Theuniformityofflowfieldinthebasin,suchashorizontalandverticalcurrentvelocityprofiles,werecalculatedindetail.Besides,a1:10scaledmodeltestwasalsocarriedout.Thecurrentvelocitiesatdifferentlocationsinthebasinweremeasuredandcomparedwiththecalculatedresults.Itisconcludedthatsatisfactoryagreementcanberesultedbetweenthenumericalsimulationandmodeltest.Inaddition,itissuggestedthattransitionsectionsandturningvanesneedtobesetininflowandoutflowculvertstoimprovetheuniformityofflowfieldinthebasin.Andthehydraulicperformanceofthedeepwatercurrentgenerationsystemcanmeettherequirementsofmodeltestsindeepwater.

简介：

简介：ATime-domainHigher-OrderBoundaryElementMethod(THOBEM)isdevelopedforsimulatingwave-currentinteractionswith3-Dfloatingbodies.ThroughaTaylorseriesexpansionandaperturbationprocedure,themodelisformulatedtothefirst-orderinthewavesteepnessandinthecurrentvelocity,respectively.Theboundaryvalueproblemisdecomposedintoasteadydouble-bodyflowproblemandanunsteadywaveproblem.Higher-orderboundaryintegralequationmethodsarethenusedtosolvetheproposedproblemswithafourth-orderRunge-Kuttamethodforthetimemarching.Anartificialdampinglayerisadoptedtodissipatethescatteringwaves.Differentfromtheothertime-domainnumericalmodels,whichareoftenfocusedonthewave-currentinteractionwithrestrainedbodies,thepresentmodeldealswithafloatinghemisphere.Thenumericalresultsofwaveforces,waverun-upandbodyresponseareallinacloseagreementwiththoseobtainedbyfrequency-domainmethods.Theproposednumericalmodelisfurtherappliedtoinvestigatewave-currentinteractionswithafloatingbodyofcomplicatedgeometry.Inthiswork,theregularandfocusedwavecombinedwithcurrentinteractingwithatruss-sparplatformisinvestigated.

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

简介：Athree-dimensional(3-D)numericalmodelisestablishedtoinvestigatethetidalcurrentmotioncharacteristicsaroundtheharborentrance.Computationalapproachesconsistofthefinitedifferencemethod,time-splittingtechnique,C-grid,andahigh-orderturbulenceclosuremodel.TheOceanGeneralCirculationModel(OGCM)inundationschemeisincorporatedinthemodel.Anengineeringapplication,LianyungangHarbor,China,isusedasareal-lifecase.Themodelisvalidatedbyshowingthatthesimulatedresultsagreewellwiththefielddata.Intheapproachchannel,thetidalcurrentshowsadeflectioneffectespeciallyinthebottomlayer.AsforLianyungangHarbor,ajetflowformsatthetipofthenorthernbreakwater,whichdrivesacirculationflowattheinnersideoftheharborentrance.Inthevertical,theflowissignificantlystratifiedattheentrancesectionwithinthechannel,wheretheflowdirectionvariesbetweenlayersandthespeeddistributionisquiteuniform.These3-Dfeaturesbecomelessevidenttotheoffshore.Additionally,thesensitivityanalysisshowsthattheflowdeflectionisrelatedtothechanneldepth.Simulationresultsalsoimplythatthesiltationrateattheentrancesectionoftheapproachchanneltendstobemoreuniformbythe3-Dflowmotionfeature,andcouldbemoresignificantwiththeincreaseofthechanneldepth.

简介：CoupleddynamicanalysisoftheDeepDraftMulti-Spar(DDMS)platformandthemooringsystemundertheactionofwavesandcurrentiscarriedoutinthetimedomain.Usingageometricallynonlinearfiniteelementmethod,themooring-linedynamicsissimulatedbasedonthetotalLagrangianformulation.WavegroupsareobtainedbytheJONSWAPspectrumandanempiricalwaveenvelopespectruminvolvingtwoenvelope-basedfactorsGroupHeightFactor(GFH)andGroupLengthFactor(GLF).Theresultsshowthatthewavegroupshaveasignificanteffectonthemotionresponsesoftheplatformandthemooringlinetensions.

简介：InspiredbyDryobalanopsaromaticaseed,anewbiomimicrymarinecurrentturbineisproposed.Hydrodynamicperformanceandwakepropertiesaretwokeyfactorsdeterminingwhetheranewmarinecurrentturbinedesignispracticalornot.Thus,astudyofhydrodynamicperformanceandwakeoftheproposedbiomimicryturbineisconducted.Thecomputationalfluiddynamics(CFD)software,OpenFOAMisusedtogeneratetherequiredresultsforthementionedstudy.ThehydrodynamicperformanceandwakepropertiesoftheproposedbiomimicryturbineiscomparedtotwoconventionalturbinesofBahajetal.andPinonetal.respectively.Thesimulationresultsshowedthattheproposedbiomimicrymarinecurrentturbinegivesoptimumpoweroutputwithitspowercoefficient,0.376PC≈atthetipspeedratio(TSR)of1.5.Underthesameboundaryconditions,themaximumtorqueproducedbytheproposedbiomimicryturbineatzerorotationalspeedis38.71Nmwhichis1110%greaterthanthetorquegeneratedbytheturbineofBahajetal..Therecoverydistanceforthewakeofthebiomimicryturbineispredictedtobe10.6%shorterthanthatofIFREMER-LOMCturbine.Theabove-mentionedresultsconfirmthepotentialapplicationoftheproposedbiomimicrymarinecurrentturbineintherenewableenergyindustry.

简介：Thehydraulicandsedimentdepositionproblemsinthewaterintakesystemofapumpinghousewerestudiedbyphysicalmodel.Theexperimentalresultsofdifferentworkingcasesindicatethatthesedimentdepositionsatthegates,stillingbasinandculvertsareveryfewwhenthesystemwasnormallyoperated,butintheforebayofpumpinghouse,especiallyinthepumpinghouseforlivingwater,theamountofsedimentdepositionsometimesisconsiderablylarge.Atthefrontoftheentryofpumpinghouseforlivingwater,installingasetofobliquepipescanpreventthecoarsegrainstoenterit,thedepositionamountwillobviouslydecrease.

简介：Physicalmodeltestswerecounductedtopredictlocalscourandmaximumscourdeptharoundthelargediametercylinderslocatedinthe(sand)seabedundertheactionofbothwaveandcurrent.Accordingtotheresultoftests,ananalysiswasmadeonallthefactorsinfluencingthescour.Theresultsshowsthatfortheseabedwithrelativefinegrainsinshallowwater(0.07＜h/L≤0.28),whentherelativediameterD/Lofthecylinderiswithin0.3-0.7,themaineffectivescourfactorsaroundthecylinderintheseabedarediameterDofthecylinder,thewaveheightH,thewavelengthL,thevelocityVcofthecurrentandtheparametersrelatedtotheseabedsoiltexture.Themainparametersinfluecingthemaximumscourdepthwereanalyzed,andthetestdataweresyntherized,toobtaintheformulapredictingthescourdeptharoundthelargediametercylinderundertheofbothwaveandcurrent.

简介：Newtonian,QuemadaandCassonbloodviscositymodelsareimplementedinordertosimulatetherheologicalbehaviorofbloodunderpulsatingflowconditionsinapatientspecificiliacbifurcation.Theinfluenceoftheappliedbloodconstitutiveequationsismonitoredviathewallshearstress(WSS)distribution,magnitudeandoscillations,non-Newtonianimportancefactors,andviscosityvaluesaccordingtotheshearrate.ThedistributionofWSSonthevascularwallfollowsapatternwhichisindependentoftherheologicalmodelchosen.Ontheotherhand,theWSSmagnitudeandoscillationsaredirectlyrelatedtothebloodconstitutiveequationsappliedandtheshearrate.ItisconcludedthattheNewtonianapproximationissatisfactoryonlyinhighshearandflowrates.Moreover,theNewtonianmodelseemstooverestimatethepossibilityfortheformationofatheroscleroticlesionsoraneurysmsatsitesofthevascularwallwheretheWSSareoscillating.

简介：

简介：Themasstransportvelocityinathinlayerofmuddyfluidisstudiedtheoretically.Themudmotionisdrivenbyaperiodicpressureloadonthefreesurface,andthemudisdescribedbyapower-lawmodel.Basedonthekeyassumptionsoftheshallownessandthesmalldeformation,aperturbationanalysisisconducteduptothesecondordertofindthemeanEulerianvelocityinanEuleriancoordinatesystem.Thenumericaliterationmethodisadoptedtosolvethesenon-linearequationsoftheleadingorder.Fromthenumericalresults,boththefirst-orderflowfieldsandthesecond-ordermasstransportvelocitiesareexamined.Theverificationsaremadebycomparingthenumericalresultswithexperimentalresultsintheliterature,andagoodagreementisconfirmed.

简介：Inthisstudy,asemi-analyticalformulationbasedontheScaledBoundaryFiniteElementMethod(SBFEM)wasproposedandusedtoobtainthesolutionforthecharacteristicsofatwo-dimensionaldam-reservoirsystemwithabsorptivereservoirbottominthefrequencydomain.Forsimplicity,thedamwitharbitraryupstreamfaceswasassumedtoberigidandwassubjectedtoahorizontalgroundacceleration,whilethereservoirwithabsorptivebottomwasassumedtobesemi-infinite.Thereservoirwasdividedintotwosub-domains:anear-fieldsub-domainandafar-fieldsub-domain.Thenear-fieldsub-domainwitharbitrarygeometrywasmodelledbytheFiniteElementMethod(FEM),whiletheeffectsofthefar-fieldsub-domainwhichwasassumedtobehorizontalweredescribedbyasemi-analyticalformation.Thesemi-analyticalformulationinvolvedtheeffectofabsorptivereservoirbottom,aswellastheradiationdampingeffectofasemi-infinitereservoir.AFEM/SBFEMcouplingformulationwaspresentedtosolvedam-reservoircoupledproblems.Theaccuracyandefficiencyofthecouplingformulationweredemonstratedbycomputingsomebenchmarkexamples.Highlyaccurateresultsareproducedevenifthenear-fieldsub-domainisverysmall.

简介：Thepurposeofthispaperistofindsomebettermethodsforcalculatingin-lineforcesonaverticalcircularcylinderandforanalysingthehydrodynamiccoefficientsC_DandC_Minwave-currentco-existingfield.Inthispa-per,inordertocalculatehydrodynamicforces,theauthorstrytofindawayofapplyingagreatnumberofthere-sultsaboutC_DandC_Mforwave-onlyfieldinthecaseofwave-currentco-existingfield,andtheresultsaboutC_DandC_Mobtainedinregularwavesintheeaseofirregularwaves.Suchawaymaybeofsignificanceinengineeringandfurtherresearch.

简介：