简介:Theexperimentalstudiesofthewavebreakingeffectsonfreakwavegenerationarepresentedwithinafinite-depthrandomwavetraininalaboratorywavetank.Themainattentionispaidtotheabnormalindex,AI=Hmax/Hs,beingusedtocharacterizethefreakwaves,andthechangesofthecoefficientduetowavebreaking.Theresultsshowthattheoccurrenceprobabilityoffreakwaveeventsinnon-breakingwavesismuchlargerthanthatinbreakingwavesandsuchoccurrenceindeepwaterislargerthanthatinshallowwater.
简介:Waveabsorbingstructureshavebeenwidelyappliedinmanycountries.Inthepresentpaper,thewaveheightsinfrontofaverticalwaveabsorbingstructurewithrubblefoundationaswellasinthewavechamberofthestructureareanalysedusinganapproximativecalculationmethod,andthedissipatingeffectofthestructureisverified.Onthebasisoftheresultsofregularwaves,therelativewaveheightsofirregularwavesinfrontofthewaveabsorbingstructureaswellasinthechamberhavealsobeenanalysed.
简介:Basedonthetimedependentmildslopeequationincludingtheeffectofwaveenergydissipation,anexpressionfortheenergydissipationfactorisderivedinconjunctionwiththewaveenergybalanceequation,andthenapracticalmethodforthesimulationofwaveheightandwaveset-upinnearshoreregionsispresented.Thevariationofthecomplexwaveamplitudeisnumericallysimulatedbyuseoftheparabolicmildslopeequationincludingtheeffectofwaveenergydissipationduetowavebreaking.Thecomponentsofwaveradiationstressarecalculatedsubsequentlybynewexpressionsforthemaccordingtotheobtainedcomplexwaveamplitude,andthenthedepth-averagedequationisappliedtothecalculationofwaveset-upduetowavebreaking.Numericalresultsareingoodagreementwithexperimentaldata,showingthattheexpressionfortheenergydissipationfactorisreasonableandthatthenewmethodiseffectiveforthesimulationofwaveset-upduetowavebreakinginnearshoreregions.
简介:ThewaveCoriolis-Stokes-Force-modifiedoceanmomentumequationsarereviewedinthispaperandthewaveStokestransportispointedouttobepartoftheoceancirculations.UsingtheEuropeanCentreforMedium-RangeWeatherForecasts40-yearreanalysisdata(ERA-40data)andtheSimpleOceanDataAssimilation(SODA)version2.2.4data,themagnitudeofthistransportiscomparedwiththatofwind-drivenSverdruptransportanda5-to-10-precentcontributionbythewaveStokestransportisfound.Bothtransportsarestrongerinborealwinterthaninsummers.Thewaveeffectcanbeeithercontributionorcancellationindifferentseasons.ExaminationwithKuroshiotransportverifiessimilarseasonalvariations.Theclarificationoftheefficientwaveboundaryconditionhelpstounderstandtheroleofwavesinmasstransport.Itactsassurfacewindstressandcanbefunctionaldowntothebottomoftheageostrophiclayer.Thepumpingvelocitiesresultingfromwave-inducedstressarezonallydistributedandaresignificantinrelativelyhighlatitudes.Furtherworkwillfocusonthemodelperformanceofthewave-stress-changed-boundaryandtheroleofswellsintheeasternpartoftheoceans.
简介:Theauthorsmakeanendeavortoexplainwhyanewhybridwavemodelishereproposedwhenseveralsuchmodelshavealreadybeeninoperationandtheso-calledthirdgenerationwavemodejisprovingattractive.Thispartofthepaperisdevotedtothewindwavemodel.Bothdeepandshallowwatermodelshavebeendeveloped,theformerbeingactuallyaspecialcaseofthelatterwhenwaterdepthisgreat.Thedeepwatermodelisexceptionallysimpleinform.Significantwaveheightistheonlyprognosticvariable.Incomparisonwiththeusualmethodstocomputetheenergyinputanddissipationsempiricallyorby"tuning",theproposedmodelhasthemeritthattheeffectsofallsourcetermsarecombinedintoonetermwhichiscomputedthroughempiricalgrowthrelationsforsignificantwaves,theserelationsbeing,relativelyspeaking,easierandmorereliabletoobtainthanthoseforthesourcetermsinthespectralenergybalanceequation.Thediscretepartofthemodelandtheimplementationofthemode
简介:Thestatisticaldistributionofwavecrestcharacteristicssuchascrestlength,crestheight,jointcrestheightandlengthareanalyzedbasedonnumericalsimulationof3-Drandomwaves.Theeffectsofdirectionalfunctionsandwavecrestdefiningmethodsoncrestcharacteristicsarealsostudied.Theresultsshowthatwavecrestsarenolongeruniformandcontinuousindirectionalwavefield;thedistributionofcrestlengthisobviouslyinfluencedbythedirectionalfunction;thestatisticsofcrestcharacteristicsobtainedbythetwodifferentmethodsarealmostthesame.
简介:Anewmethodoftreatingmaximumwaveheightasarandomvariableinreliabilityanalysisofbreakwatercaissonsisproposed.Themaximumwaveheightisexpressedasthesignificantwaveheightmultipliedbytheso-calledwaveheightratio.Theproposedwaveheightratioisatypeoftransferfunctionfromthesignificantwaveheighttothemaximumwaveheight.Undertheconditionofabreakingwave,theratioisintrinsicallynonlinear.Therefore,theprobabilitydensityfunctionforthe
简介:Regularandirregularwaveforcesactingonverticalwallsarestudiedbyapreviouslydevelopednumericalmodel.Thecomputedwaveforcesarecomparedwiththeavailableexperimentaldatatoverifythenumericalmodel,andsatisfactoryagreementsareobtained.Thevariationofwaveforceswithincidentanglesandtheshapeofsimultaneouspressuredistributionareinvestigated,andthecomparisonsbetweennumericalresultsandGoda'spredictionsarealsocarriedout.Itisconcludedthatthemaximumwaveforcesactingontheunitlengthofverticalwallisofteninducedbytheobliquelyincidentwavesinsteadofnormallyincidentwaves,whileGoda'sformulamaybeinapplicableforobliquewaveincidence.Theshapeofsimultaneouspressuredistributionisnotsignificantlyinfluencedbyincidentangles,anditcanbefavorablypredictedbyGoda'sformula.WhenregularwaveheightsaretakenasthesameasirregularwaveheightH1%,theirregularwaveforcesPh,1%areslightlylargerthanregularwaveforcesinmostcases.
简介:Someauthorshavedevelopedafewmethodsofmeasuringwaveslopesbasedonlightrefraction,includingthemeasurementmethodviathedistributionoflightintensityorcolorunderwater.Anewmethodbasedonlightrefractionisspecifiedforthemeasurementofwavesurfaceelevationinwaveflumeviaimagingtechnology.Aplanepaintedwithblackandwhitestripesisputontheflumefloorasanindicationplane,whichcanbearrangedeasilyandcheaply.Comparedwiththepreviousmethods,thepresentmethodislesssensitivetothenoiseandnonlineareffectsofopticalprocess,whichcanbetakenasadigitalmethod.TheCCDcameraisfixedabovetheflumewithitsopticalaxisarrangedverticallytograbtheimagesofstripesmodulatedbythewavesurface.ThemodulatedvaluecanbecalculatedfromtheHilberttransform,andthenthewavesurfaceelevationcanbeobtained.Thealgorithmandexperimentalprocedurearespecifiedindetail,andsomeexperimentalresultsareprovidedtoshowthevalidityofthepresentmethod.
简介:Alaboratoryexperimentwasconductedinsideawindwavetanktoinvestigatethewaveinducedturbulence.Inthisexperiment,thewavesurfaceelevationandvelocitybeneaththewatersurfaceweremeasuredsimultaneouslytoinvestigatetherelationbetweenthewavestatusandwaveinducedturbulence.TheprofileoftheturbulentdissipationrateandReynoldsstresswerecalculatedusingexperimentaldata.Theeffectofthewavestatusonturbulenceisinvestigatedwithregardtothewindwave,swell,andmixedwaveconditions.Itwasdepictedthattheturbulencedecreasedwithincreasingdepthfromthewatersurfaceandthattheturbulencethatwasinducedbyawavewithlargerwavelengthandwaveheightismuchstrongerforthesamewavestatus.Finally,weobservedthatthewindwaveismoreeffectiveinactivatingthewaveinducedturbulence.
简介:Consideringthatatpresenttheregularwavesincommonusehavetheprofilesymmetrizedtoaverticalaxis,whicharedifferentfromactualwind-drivenseawaves,andbasedonderivinglinearwave,solitarywave,fifthorderStokeswaveandstreamfunctionwavebyusingUnifiedVariationalPrincipleofWaterGravityWave(UVPWGW),thispaperderiveswind-drivenslantingprofilewavebyusingUVPWGW.Itsfeatureisthatundertheactionofwindpressure,thewaveprofileisnotsymmetrizedtoaverticalaxis,butthatitisintheforwardslantingform.
简介:Waveenergyhasdrawnmuchattentionasanachievablewaytoexploittherenewableenergy.Atpresent,inordertoenhancethewaveenergyextraction,mosteffortshavebeenconcentratedonoptimizingthewaveenergyconvertorandthepowertake-offsystemmechanicallyandelectrically.However,focusingthewavepowerinspecificwavefieldcouldalsobeanalternativetoimprovethewaveenergyextraction.Inthisexperimentalstudy,theBraggresonanceeffectisappliedtofocusthewaveenergy.BecausetheBraggresonanceeffectoftherippledbottomlargelyamplifiesthewavereflection,leadingtoasignificantincreaseofwavefocusing.Achievedwithanenergyconversionsystemconsistingofapointabsorberandapermanentmagnetsinglephaselinearmotor,thewaveenergyextractedinthewaveflumewithandwithoutBraggresonanceeffectwasmeasuredandcomparedquantitativelyinexperiment.ItshowsthatenergyextractionbyapointabsorberfromastandingwavefieldresultedfromBraggresonanceeffectcanberemarkablyincreasedcomparedwiththatfromapropagatingwavefield(withoutBraggresonanceeffect).
简介:Theanalysisofthedataofmodeltestsoftwolargedeepwharvesandmonographicexperimentalstudiesshowthattwoaspectsaretobeimprovedsoastopredictthewaveupliftforcesonthebottomofacircularcylinder.Thefirstaspectistheupliftpressuredistributiononthebottom,andthesecondisthecorrectdeterminationofthephaseformaximumhorizontalwaveforces.Thesecondproblemhasbeensolved.Synthesizingtheresultsoftheoreticalanalysisandexperiments,wesuggestadiagramforthedeterminationofthephasewhenthemaximumhorizontalwaveforceappears.Onthebasis-efthediagramthesimultaneouswaveupliftforcescanbeobtainedforthestructuralstabilityanalysis.
简介:-Waverefraction-diffractionduetoalargeoceanstructureandtopographyinthepresenceofa’currentarestudiednumerically.Themathematicalmodelisthemild-slopeequationdevelopedbyKirby(1984).Thisequationissolvedusingafiniteandboundaryelementmethod.Thephysicaldomainisdevid-edintotworegions:aslowlyvaryingtopographyregionandaconstantwaterdepthregion.Forwavespropagatingintheconstantwaterdepthregion,withoutcurrentinterfering,themild-slopeequationisthenreducedtotheHelmholtzequationwhichissolvedbyboundaryelementmethod.Invaryingtopographyregion,thisequationwillbesolvedbyfiniteelementmethod.Conservationofmassandenergyfluxofthefluidbetweenthesetworegionsisrequiredforcompositionofthesetwonumericalmethods.Thenumericalschemeproposedhereiscapableofdealingwithwaterwaveproblemsofdifferentwaterdepthswiththemaincharactersofthesetwomethods.