简介:Theinceptionoftipvortexcavitationisverysensitivetowaterquality.Inordertoquantifytheeffectofwaterqualityontheinceptionoftipvortexcavitation,wedevelopamotionmodeltodescribethemigrationandgrowthofnucleiinwater.Ananalyticalsolutionofmigrationofnucleiinavortexflowisobtainedsothatthecapturetimesofvariousnucleicanbegivenoutdirectly.Acriterionisbuilttodeterminethecriticalnucleusinacertainnucleispectradistribution.Tensilestrengthofthecriticalnucleusisusedtoquantifytheeffectofwaterqualityandcorrectthetipvortexcavitationinceptionnumber.Finallythischangeofcavitationinceptionnumberiscomparedwithexperimentalresultstovalidateourmodel.
简介:InordertosimulatethecharacteristicsofhydrodynamicfieldandmasstransportprocessesintheYuqiaoReservoir(YQR),a2-Dcoupledmodelofhydrodynamicsandwaterqualitywasdeveloped,andthewater-qualityrelatedstatevariablesinthismodelincludedCODMn,TNandTP.Thehydrodynamicmodelwasdrivenbyemployingobservedwindsanddailymeasuredflowdatatosimulatetheseasonalwatercycleofthereservoir.ThesimulationofthemasstransportandtransformationprocessesofCODMn,TNandTPwasbasedontheunsteadydiffusionequations,drivenbyobservedmeteorologicalforcingandexternalloadings,withthefluxesformthebottomofreservoirandtheplantphotosynthesisandrespirationasinternalsourcesandsinks.AfinitevolumemethodandAlternatingDirectionImplicit(ADI)schemewereusedtosolvetheseequations.ThemodelwascalibratedandverifiedbyusingthedataobservedfromYQRintwodifferentyears.TheresultsshowedthatinYQR,thewind-drivencurrentwasanimportantstyleoflakecurrent,whiletheconcentrationofwaterqualityitemwasdecreasingfromeasttowestbecauseoftheexternalpollutantloadings.Therewasagoodagreementbetweenthesimulatedandmeasuredvalues,withtheminimalcalculationerrorpercentof0.1%and2.6%andthemeanerrorpercentof44.0%and51.2%forTNandTPseparately.Thesimulationalsoshowedthat,inYQR,theconvectionwasthemainprocessinestuariesofinflowriver,anddiffusionandbiochemicalprocessesdominateincenterofreservoir.Soitwasnecessarytobuildapre-pondtoreducetheexternalloadingsintothereservoir.