简介：Throughaseriesofmodeltests,thewaveforcesonhorizontalandinclinedcircularcylindersaremeasuredandanalyzed.BasedonMorisonEquationandStokessecondorderwavetheory,therelationshipbetweenthehydrodynamicforcecoefficientswithKCnumberandsub-mergedwaterdepthaswellforhorizontalcylindersareanalyzed,alsotherelationshipbetweenthehydrodynamicforcecoefficientswithKCnumber,inclinedangleandtheeffectofwaterfreesurfaceaswellfortheinclinedcylindersareinvestigated.

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简介：Theflowbehindathree-dimensionalrotationallyoscillatingcircularcylinderwasstudiedbyanumericalmethod.ThecomputationswereperformedataReynoldsnumberof260,whichisatalevelthattheflowwakehasdevelopedintoathree-dimensionalstatecalledMode-B.Thepurposeofthispaperistoexaminetheinfluenceofvariousrotationalamplitudes(0.1-0.7)onthewakeinstabilityoftheflow,whiletheoscillationfrequencyisfixedtothevalueofthatmeasuredinthewakeofastationarycylinder.Theresultsshowthattherotationwithsufficientlyhighamplitudebringstheflowbacktoitsnominaltwo-dimensionalstate.Moreover,itisfoundthatthevalueofthetime-averageddragandtheRMSvalueoftheliftarelargerthanthoseofastationarycircularcylinder.

简介：Oscillatingflowaroundacircularcylinderinthevicinityofaplanewallwasinvestigatedbysolvingthetwo-dimensionalincompressibleNavier-StokesequationswithafiniteelementGalarkinresidualmethod.TheeffectofthegapGDbetweenthecylindersurfaceandthewallontheflowbehaviorwasstudied.ForthecaseofGD≤0.25,theperiodicityintheflowisattributedtoboththeoutershearlayerinstabilityandtheoscillatingfrequency.AsGD>0.25,vortexsheddingoccursandtheperiodicityintheflowismainlyduetothecompetitionoftheoscillatingfrequencyandthevortexsheddingfrequencyfromanisolatedstationarycylinder.

简介：TheseparatedturbulentflowaroundacircularcylinderisinvestigatedusingLarge-EddySimulation(LES),Detached-EddySimulation(DES,orhybridRANS/LESmethods),andUnsteadyReynolds-AveragedNavier-Stokes(URANS).Thepurposeofthisstudyistoexaminesometypicalsimulationapproachesforthepredictionofcomplexseparatedturbulentflowandtoclarifythecapabilityofapplyingtheseapproachestoatypicalcaseoftheseparatedturbulentflowaroundacircularcylinder.Severalturbulencemodels,i.e.dynamicSub-gridScale(SGS)modelinLES,theDES-basedSpalart-Allmaras(S-A)andk?ωShear-Stress-Transport(SST)modelsinDES,andtheS-AandSSTmodelsinURANS,areusedinthecalculations.Sometypicalresults,e.g.,themeanpressureanddragcoefficients,velocityprofiles,Strouhalnumber,andReynoldsstresses,areobtainedandcomparedwithpreviouscomputationalandexperimentaldata.Basedonourextensivecalculations,weassessthecapabilityandperformanceofthesesimulationapproachescoupledwiththerelevantturbulencemodelstopredicttheseparatedturbulentflow.

简介：一个分析方法被建议在二层的液体由装底部的圆形的柱体分析放射和衍射ofwater波浪。分析表情foradded质量和抑制系数，以及圆形的cylinderwere的波浪刺激力量由一个特徵函数扩大方法获得了。在二层的液体的bottom-mountedcircular柱体上的水动力学力量包括不仅增加的团和抑制系数，butalso表面的波浪力量和内部波浪的模式。这与ahomogenous液体的盒子不同。一些例子被给，证明密度层化能有在大量频率上的这些水动力学力量上的relativelarge效果。

简介：FlowsaroundacircularcylinderdisplayinganunsteadyvortexsheddingprocessattheReynoldsnumbersof1000,3900and1×104arestudiedusingafinite-volumeTotalVariationDiminishing(TVD)schemeforsolvingtheUnsteadyReynolds-AveragedNavier-Stokes(URANS)equations.AnElementalVelocityVectorTransformation(EVVT)approachisproposedforthelocalnormalandtangentialvelocitytransformationattheinterfacesofmainandsatelliteelements.Thepresentedmethodisvalidatedbycomparingwiththeavailableexperimentaldataandnumericalresults.Itisshownthatthetwo-dimensionalTVDfinitevolumemethodwiththeRenormalizationGroup(RNG)turbulencemodelcanbeusedtodeterminehydrodynamicforcesandcapturesvortexsheddingcharacteristicsverywell.

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：Inthispaper,aniterationmethodispresentedtocalculatethesteadynoseparationflowpastacircularcylinderwithbrokenline-shapedvelocityprofile.Ateachiterationstep,thestreamlinesofthelaststepareconsideredasequivorticitylinestodeterminethenewflowfield.Theiterativeprocessisstoppedwhencertainconvergencecriterionisreached.Severalexamplesaregivenwhichshowtheeffectivenessofthemethod.

简介：Adimpleappearsonafreesurfacewhilerotatingacylindertankfilledwithliquid.Thedimplestartstoconcentricallydeepertoadrainportatthebottomcenterofthetank.Overtime,thedimplepenetratesthedrainport,afreesurfaceformsalongandslenderstringshapeinthetank,andaso-calledvortexing(aircore)phenomenonoccurs.Thegenerationofavortexcoredependsonthesizeofthetankanddrainport,andonthepropertiesoftheliquidinthetank.Inthisstudy,theliquidlevelandthetimeatwhichthevortexcoreisinitiallygeneratedarenumericallyinvestigatedusingdifferentvaluesoftankdiameter,drainportdiameter,andinitialtankrotationalspeeds.Insteadofafullthree-dimensionalanalysis,atwo-dimensionalaxisymmetricsimulationisconducted.Themomentumconservationequationinthecircumferentialdirectionisadditionallysolvedinthetwo-dimensionalmeshsystem.Severalnon-dimensionalvariablesarecreated:theratiooftheaircoregenerationdistanceandtankdiameter,thediameterratioofthetankanddrainport,therotationalReynoldsnumber,therotationalFroudenumber,andtherotationalWebernumber.Finally,thenon-dimensionalaircoregenerationdistanceiscorrelatedwiththeothernon-dimensionalparameters.

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