简介:TheTangjiashanlandslidedamfailedonJune10,2008,whichwasthelargestoneformedduringtheWenchuanearthquakeinChina.Nohumanliveswerelostinthisdamfailure.Thispaperpresentsadescriptionofthedam,includingthedamgeometry,thehydrographandthereservoircapacity,thediversionchannelandthedrainagefromthelake.Severalempiricalmodelsareappliedtopredictthebreachparameters,thepeakoutflowsandthereservoirvolumesduringthisbreachevent.Themainobjectiveofthestudyistocomparevariouspredictionmodelsandtomakerecommendationofthebestmodelforthepredictionofthebreachwidth,thefailuretime,andthepeakoutflow.ThebreachwidthspredictedbytheFroehlichmethodswithconsiderationsofthereservoirstoragesandtheeffectoffailuremodeareconsideredtobemorereasonable.Allpredictionmethodsdiscussedinthispaperarefoundtounderestimatethebreachformationtimeduetothecomplexmaterialandthelargethicknessofthedam.Theresultsfromthesoilconservationservices(SCS)methodcomparewellwiththeobservedpeakoutflow.TheMaronemethodincombinationwiththecoefficientexpressionsproposedbyMacchionegivesexcellentresultsinthesimulationofthereservoirvolume-levelcurve.
简介:Inthisarticle,basedonriverqualitysimulationandsystemoptimization,awaterqualitymodelwasestablishedforscenicriverafterrainfalldischargeinfloodseason,withthetargetofmakingwaterpollutantsmeetthestandardinpriorityandsavingexpenditureonpollutioncontrol.Withtheprincipleofreducingsewagefromcombinedsewagepumpingstationandheavilypollutedinitialrainwater,amathematicalmultiobjectiveplanningmodelwasconstructedforrainsewagepollutioncontrolinfloodseason,andonescenicriverinanortherncitywastakenforsimulationexample.Theresultsshowthat:theoptimizationresultmeetstherequirementsofplanning,amongwhich,sewagereductionfromthecombinedpumpingstationaccountsfor17.38%inthetotalreductionofrainsewage,andthereductionintheheavilypollutedrainwateraccountsfor77.24%inthetotalreductionofrainwaterpumpingstation.Theplanningschemecanprovidetheoreticalbasisforpollutioncontrolofscenicriverinfloodseason,andforrationalreconstructionandlayoutofoutfallsalongtwobanksoftheriver.
简介:TheLudaoLakewithanareaof0.86km2and50%watersurfaceratio,wastakenasanexampletostudytheeco-hydraulicstechniquesforpreventinglakeeutrophication.Besidesexternalwaterinflowandoutflow,thetermrelatedtointernallocalflowcirculationwasaddedinthecontinuityequationoftwo-dimensionalhorizontalhydrodynamicmodel,andfurtherthehydrodynamicmodelwascalibratedbythescenarioofnowaterexchange.Thevelocityof0.2m/swassuggestedtobethecriticalvelocityofcontrollingalgalbloom.Toachievethecriticalvelocityinthewholelake,threefactorswereanalyzed,whicharewind,artificialexternalinflowaugmentationandinternallocalflowdisturbancebypumpcirculation.Itisfoundthattheroleofwindcanbedisregarded.Fortheeco-hydraulicstechniqueofexternallakewaterinflowaugmentation,thewaterflowingrouteshouldbefirstlyoptimized,further,thelakeinflowhasacriticalvalueunderspecifiedwaterlevelduetothenarrowinlets,sothewholelakeisdifficulttoreachthecriticalvelocitytopreventalgalbloom,andacombinationofexternalinflowaugmentationandinternallocalflowingdisturbanceshouldbeconsidered.Simulationresultsshowthatthecombinationofexternalwaterinflowaugmentationandinternallocalflowdisturbancerequireslesseco-flowtoachievetheglobalcriticalvelocitythanthesoleinternallocalflowdisturbance,fortheLudaoLake,theformerrequirestotaleco-flowof25m3/s,whichreducesby50%thanthelatterrequiringtotaleco-flowof52m3/s.
简介:WiththerapiddevelopmentofhighdamprojectswithinChina,thedragon-drop-tailspillwaytunnelisintroducedandwidelyused.Inviewofthehighwaterheadandthelargeflowvelocityonthedragon-drop-tailsection,aeratordevicesareusuallyplacedforthecavitationdamagecontrol.Forthedeviceplacedinitsinitialposition,itisaseriousconcerntodesignasuitableflowregimeofthecavityandtocontrolthecavityfillingwaterduetothelargeflowdepthandthelowFroudenumberthroughthisaerator.Inthisstudy,therelationshipsbetweenthegeometriesoftheaeratordeviceandthejetimpactangleofthelowertrajectoryoftheflowaretheoreticallyanalyzedwith/withoutalocalslope.Ninetestcaseswithdifferentgeometriesaredesigned,theeffectivenessofthefillingwatercontrolisexperimentallyinvestigatedunderdifferentoperationconditions,andtwocriteriaofthelocalslopedesignareproposed.Itisconcludedthatthecavityflowregimeandthefillingwatercanbeimprovedifasmallimpactangleandsomesuitablegeometriesofthelocalslopearedesigned.
简介:Thispaperstudiestheflowstructureandthebedloadtransportregimeinbackwaterflows,toprovideatheoreticalsupportforsolvingthesedimenttransportandbedscourproblemsinriversorreservoirswithbackwater.Thebedloadtransportratesunderdifferentconditionsareanalyzedfirstonthebasisoftheoreticalanalysis,measurementcomparisonandflumeexperiment,anditispointedoutthattheexistingformulasforthebedloadtransportratearenotapplicableforthebedloadtransportrateinbackwaterflows.Next,theflowstructureinanon-uniformflowisobservedbyflumeexperiments,andbyintroducingthebackwaterdegreeindex,thequantitativerelationbetweentherelativebedshearstressandthebackwaterdegreeisobtained.Finally,theformulaforthebedloadtransportrateapplicableforthereservoirchannelsegmentwithbackwaterflowsisobtainedthroughmeasurementsandflumeexperiments.
简介:TheFilteringGridScale(FGS)ofsub-gridscalemodelsdoesnotmatchwiththetheoreticalProperFGS(PFGS)becauseoftheimpropermesh.Therefore,properLargeEddySimulation(LES)Meshisverydecisiveforbetterresultsandmoreeconomicalcost.Inthiswork,thepurposeistoprovideanadaptivecontrolstrategyforproperLESmeshwithturbulencetheoryandCFDmethods.AnewexpressionofPFGSisproposedonthebasisof-5/3lawofinertialsub-rangeandthepropermeshofLEScanbebuiltdirectlyfromtheadjustmentofRANSmesh.Abenchmarkofthebackwardfacingstepflowatisprovidedforapplicationandverification.Therearethreekindsofmeshsizes,includingtheRANSmesh,LAM(LESofadaptive-controlmesh),LFM(LESoffinemesh),employedhere.ThegridnumberofLAMissmallerthanthoseofLFMevidently,andtheresultsofLAMareinagoodagreementwiththoseofDNSandexperiments.ItisrevealedthattheresultsofLAMareveryclosetothoseofLFM.Theconclusionsprovidepositiveevidencesforthenovelstrategy.
简介:Inthispaper,thehydrodynamiccharacteristicsofwaterflowinChaohuLakearestudiedbyusingthefinitevolumecoastaloceanmodel(FVCOM),whichisverifiedbytheobserveddata.Thetypicalflowfieldandthe3-Dflowstructureareobtainedforthelake.Theflowfieldsunderextremeconditionsareanalyzedtoprovideaprospectiveknowledgeofthewaterexchangeandthetransportprocess.Theinfluenceofthewindontheflowisdeterminedbythecrossspectrummethod.Theresultsshowthatthewind-drivenflowdominatesmostareaofthelake.Underprevailingwindsinsummerandwinter,thewaterflowstowardsthedownwindsideattheupperlayerwhiletowardstheupwindsideatthelowerlayerinmostareaexceptthataroundtheChaohuSluice.Theextremewindspeedisnotfavorableforthewaterexchangewhilethesluice’sreleasingwateracceleratestheprocess.Thewatervelocityinthelakeiscloselyrelatedwiththewindspeed.
简介:Duetotheinteractionbetweenthemainhullandsidehulls,differentlayoutsandlengthsofsidehullsaffectthewaveloadssignificantly.Basedonthree-dimensionalpotentialtheoryandGreen'sfunction,thisarticlegivesthesignificantvaluesforwaveloads,includingverticalshearforcesandverticalbendingmomentsatdifferentlocationsonthemainhull,andtransversebendingmomentsatthejunctionofthecrossstructureandmainhull.Inaddition,aparametricoptimizationofwaveloadsfordifferentlayoutsandlengthsofsidehullswereperfomed.Severalspeedsandwaveheadingswerealsoconsidered.Finally,spectralanalysiswasconductedtoattainloaddistribution.Theconclusionsofthisstudyareconducivetothedesignandoptimizationofthisnewtypeofship.
简介:Thedragreductionofcompliantsurfaceisstudiedinashipmodeltank.There-sultsofthemeasureddragofaflatplatemodelshowthatthecompliantsurfaceiscapableofre-ducingdraginacertainrangeofspeeds,Themaximumdragreductionis15.7%whenthecom-pliantsurfaceismerelyontheonesideoftheplate.Theseresultshaveconfirmedthepredictedcharacteristicsofcompliantsurfaces.
简介:Chinabearsahighreliefinthewestandlowintheeast,withcomplextopography,totaling2/3ofthewholecountry'sareaformountains,hillyregionsandzigzagplateaus.Thereforethehydraulicresourcesareabundant,withpotentialhydraulicamountofabout680000MW,ofwhich,smallhydropowerresourceisveryrichtooandhasgreatexploitablepotential.Accordingtogeneralinvestigationinearly1980s,theexploitableamountreached87000MW,rankingthetopintheworld.
简介:Amulti-functionsamplingsystemhasbeensetupinShanghaiShip&ShippingResearchInstitute(SSSRI)whereatestonthefluctuatingpressureoftwopropellermodelswerecarriedout.Thispaperdealswithastudyonthetechnicalproblemsconcerningthemeasurementandanalysistechniquesinvolvedinthetest.Thesamplingandprocessingprocedureofsignalisoneofthemajorfactorsaffectingtheac-curacyandstabilityofthepredictionoffluctuatingpressureinducedbypropeller.Integral-peri-odsampling,highenoughsamplingfrequencyandsuitableresolutionmustbekeptinsamplingandprocessing.Theprocedureofsamplingandprocessingshouldbevalidatedbystandardsignalcorrespondingtothebladefrequencyofdifferentordersincomparativetests.
简介:Aninvestigationoftheventilatedsupercavitationforasupercavitatingvehiclepitchingupanddowninthesupercavitywascarriedoutinahigh-speedwatertunnel.Theemphasisislaidontheunderstandingoftheinteractionofthevehicleaftbodywiththecavityboundary.Theflowcharacteristicsweremeasuredandthestabilityofsupercavitingflowwithdifferentpitchingfrequenciesandamplitudeswasanalyzed.Inparticular,theobjectivesofthisstudyaretounderstandtheeffectoftheimpactuponthecavitydistortion,andtoquantifytheimpactprocessbyinvestigatingtheevolutionofthepressureinsidethecavityandthentheloadsonthevehicleduringthepitchingmotion.Itisalsoshownthattheevolutionofthepressuredetectedindifferent,asinsidethesupercavity,iscoherentanduniformduringtheperiodsofthepitchingmotion.Thisstudyisofdirectrelevancetoreliableandaccuratepredictionofhydrodynamicloadsassociatedwiththeslammingandimpactonsupercavitatingvehicles.
简介:AnexperimentalapparatustoinvestigateACMHDpumpwasestablished,whichmainlyconsistsofarotarypermanentmagnetwith4polesanannularchannel,amotor,ashaftandaplatform.Themagnetgeneratesafieldsimilartosinusoidwiththemaximumof0.9TinthechannelwhenitisrotatedupbythemotortosimulateanACmagneticfield.Thismovingmagneticfieldactsontheconductivefluidinthechannel,andproducesanelectromagneticforcetomovethefluidinthesamedirectionasthatofthemagnetrotating.Experimentswerecarriedouttoinvestigatetheperformanceofthepump.Flowvelocityintheannularchannelwasmeasuredfordifferentconductivitiesandrotatingspeedsofthemagnet.Theresultsshowthattheflowrateandpressureincreaseasthemagneticfieldstrength,fluidconductivityandfrequencyofthemagneticfieldincrease.
简介:Particleimpactdrillingisanefficientdrillingtechnologyfordeep-wellhardformation,Withthistechnology,therockiscutmainlybyhigh-speedsphericalparticleimpactunderhydraulicaction.Inthisarticle,theinfluenceofjetflowfactors,hydraulicfactorsandabrasivefactorsonrockbreakingisstudiedthroughindoorexperimentsofimpactbysteelparticles.Theresultsindicatethattheparticlewaterjethasanoptimalstandoffdistanceandparticleconcentration;therockbreakingeffectdeclineswiththeincreaseoftheconfiningpressureandthedecreaseofthepumppressureandparticlediameter.Thisstudywillprovidesomefoodofthoughtforthedevelopmentofparticleimpactdrillingtechnology.
简介:Thepier,placedattheoutletofthepressureflowsection,isaneffectivedesigntodealwiththeproblemsofthemanufactureandoperationofthegatesforadischargetunnelwithhighwaterhead.Itiscrucialtocontrolthewater-wing,inducedbythistypeofthepier.Throughobservingthephenomenaofthewater-wing,thereasonofthewater-winginception,i.e.,theconcaveoftheflowsurface,waspresented,andatypeofthenewpierwithbottomunderlaywasdesigned.Thehydrauliccharacteristicsofthepier,includingthevariationsofthewater-wingfeatures,bothlengthandheight,withthewaterhead,aswellaswiththeconcavedepth,andwiththeheightofthebottomunderlay,andthevariationsoftheconcavedepthwiththeheightofthebottomunderlay,wereinvestigatedbyphysicalmodelexperiments.Theresultsshowthattheapproachofthemodificationoftheconcavethroughthestructureswiththebottomunderlay-typepierisremarkablyeffectiveinthewater-wingcontrol.
简介:FordeepfoundationpitdewateringintheYangtzeRiverDelta,itiseasytomakeadramaticdecreaseoftheundergroundwaterlevelsurroundingthedewateringareaandcauselandsubsidenceandgeologicdisasters.Inthiswork,athree-dimensionalfiniteelementsimulationmethodwasappliedintheforthsubwayofDongjiadutunnelrepairfoundationpitdewateringinShanghai.Inordertocontrolthedecreaseoftheundergroundwaterlevelaroundthefoundationpit,thefoundationpitdewateringmethodwasusedtodesigntheoptimizationprojectofdewatering,whichwassimulatedundertheseconditionsthattheaquifersdepositedlayerbylayer,thebottomoftheaquiferswentdeepto144.45m,theretainingwalloffoundationpitshieldwentdeepto65m,thefiltersoftheextractionwellswerelocatedbetween44mto59m,thewaterlevelinthedeepfoundationpitwasdecreasedby34m,andthemaximumdecreaseofwaterleveloutsidethefoundationpitwas3m.Itisshownthattheoptimizationprojectandthepracticalcaseareconsistentwitheachother.Accordingly,thethree-dimensionalfiniteelementnumericalsimulationisthebasictheoryofoptimizationdesignofengineeringstructuresofdewateringindeepfoundationpitinsuchareas.
简介:Thehydraulicandsedimentdepositionproblemsinthewaterintakesystemofapumpinghousewerestudiedbyphysicalmodel.Theexperimentalresultsofdifferentworkingcasesindicatethatthesedimentdepositionsatthegates,stillingbasinandculvertsareveryfewwhenthesystemwasnormallyoperated,butintheforebayofpumpinghouse,especiallyinthepumpinghouseforlivingwater,theamountofsedimentdepositionsometimesisconsiderablylarge.Atthefrontoftheentryofpumpinghouseforlivingwater,installingasetofobliquepipescanpreventthecoarsegrainstoenterit,thedepositionamountwillobviouslydecrease.