简介：1.INTRODUCTIONInconnectionwithexperimentalmodelinvestigationsofcavitationphenomenaatsubmergedbodiessocalledscaleeffectscanoccur.Inordertobeabletopredictthecavitationbehaviourofaprototypefrommodeltests,thesescaleeffectsmustbeknownandbetakenintoaccountbysimu-larityrelations.Inpreviousinvestigationstestbodyfamiliesofdifferentshapesandsizewereinvestigatedinwaterofdifferenttensilestrengthforcavitationinception.

简介：WiththerapiddevelopmentofhighdamprojectswithinChina,thedragon-drop-tailspillwaytunnelisintroducedandwidelyused.Inviewofthehighwaterheadandthelargeflowvelocityonthedragon-drop-tailsection,aeratordevicesareusuallyplacedforthecavitationdamagecontrol.Forthedeviceplacedinitsinitialposition,itisaseriousconcerntodesignasuitableflowregimeofthecavityandtocontrolthecavityfillingwaterduetothelargeflowdepthandthelowFroudenumberthroughthisaerator.Inthisstudy,therelationshipsbetweenthegeometriesoftheaeratordeviceandthejetimpactangleofthelowertrajectoryoftheflowaretheoreticallyanalyzedwith/withoutalocalslope.Ninetestcaseswithdifferentgeometriesaredesigned,theeffectivenessofthefillingwatercontrolisexperimentallyinvestigatedunderdifferentoperationconditions,andtwocriteriaofthelocalslopedesignareproposed.Itisconcludedthatthecavityflowregimeandthefillingwatercanbeimprovedifasmallimpactangleandsomesuitablegeometriesofthelocalslopearedesigned.

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.

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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.

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简介：Inthisarticle,basedonriverqualitysimulationandsystemoptimization,awaterqualitymodelwasestablishedforscenicriverafterrainfalldischargeinfloodseason,withthetargetofmakingwaterpollutantsmeetthestandardinpriorityandsavingexpenditureonpollutioncontrol.Withtheprincipleofreducingsewagefromcombinedsewagepumpingstationandheavilypollutedinitialrainwater,amathematicalmultiobjectiveplanningmodelwasconstructedforrainsewagepollutioncontrolinfloodseason,andonescenicriverinanortherncitywastakenforsimulationexample.Theresultsshowthat:theoptimizationresultmeetstherequirementsofplanning,amongwhich,sewagereductionfromthecombinedpumpingstationaccountsfor17.38%inthetotalreductionofrainsewage,andthereductionintheheavilypollutedrainwateraccountsfor77.24%inthetotalreductionofrainwaterpumpingstation.Theplanningschemecanprovidetheoreticalbasisforpollutioncontrolofscenicriverinfloodseason,andforrationalreconstructionandlayoutofoutfallsalongtwobanksoftheriver.

简介：采用内循环生物流化床系统，进行N、P废水的试验研究，通过控制曝气时间和溶解氧浓度。能同时达到脱氮除磷的效果。对于N、P废水，COD在352-1048mg／L。TN在46．9-76．4mg／L，TP在5．8-14．4mg／L时，COD、TN、TP去除率分别为92％、80％、93％，处理后的水可达到国家二级排放标准。

简介：大型项目管理P3软件代表了现代化项目管理方法和计算机最新技术；它的核心是项目管理和进度控制；它的作用是求得一个时间短、资源耗费少、费用低的项目实施管理过程。

简介：结合建筑物的结构特点利用卡西欧FX-4800P计算器编程．配合全站仪进行现场测量放样，能将施工测量中计算、施测、资料整理及校核工作同时进行，有效提高了施工测量的精度及效率，且计算器体形轻巧，便于携带和使用。