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.

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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.

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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.

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