简介：Amulti-functionsamplingsystemhasbeensetupinShanghaiShip&ShippingResearchInstitute(SSSRI)whereatestonthefluctuatingpressureoftwopropellermodelswerecarriedout.Thispaperdealswithastudyonthetechnicalproblemsconcerningthemeasurementandanalysistechniquesinvolvedinthetest.Thesamplingandprocessingprocedureofsignalisoneofthemajorfactorsaffectingtheac-curacyandstabilityofthepredictionoffluctuatingpressureinducedbypropeller.Integral-peri-odsampling,highenoughsamplingfrequencyandsuitableresolutionmustbekeptinsamplingandprocessing.Theprocedureofsamplingandprocessingshouldbevalidatedbystandardsignalcorrespondingtothebladefrequencyofdifferentordersincomparativetests.

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.