中英文對照外文翻譯(文檔含英文原文和中文翻譯)ShortandLongTermAdvantageroofdrainagedesignperformanceDecadehaswitnessedgreatchangesinthedesignoftheroofdrainagesystemrecently,particularly,siphonrainwaterdrainagesystemhasbeengraduallyimproved,andthereislikelytobethekeyapplication.Atthesametimethesechanges,urbandrainagesystemdesignhasundergonetremendouschanges,becausethescopeofawiderurbandrainagesystemdesignforsustainabledevelopment,aswellaspeopleforclimatechangefloodingmoreattention.Themaincontentsofthisarticleishowtodesignroofdrainagesystemsandmakeagoodperformance.Specialattentionishowtogetridofbadhabitsalreadyformedthedesign,butalsoneedtoconsiderinnovativeroofdrainagesystem,suchasgreenroofsandrainwaterharvestingsystems.Practicalapplication:Inthepastfewyears,thedesignoftheroofrainwaterdrainagesystemhasundergonetremendouschanges.Onlargebuildings,siphonrainwaterdrainagetechnologyhasbeenverycommon,aswellasgreenroofsbecauseitisconducivetogreendevelopment,beingmoreandmoreapplications.Takingintoaccounttheongoingresearch,thisarticlefocusesonhowtoeffectivelydesignavarietyofroofrainwaterdrainagesystem,andmakeitachievethedesireddesigneffect.1.IntroductionInthepastdecade,thecityandthewaterdrainagesystemdesignhasbeenwidelyacceptedthinkingaboutsustainableurbandrainagesystem,ortheoptimalmanagementdirection.Themainprinciplesofthedesignofthesesystemsisbothalocallevelinlinewiththequalityofdevelopment,butalsotocreatesomeeconomicbenefitsfortheinvestors.Thisprinciplehasledtothedevelopmentofnewchangesinthesump.Althoughtheapplicationofsuchadeviceisgraduallyreduced,buttheurbanenvironmentrelativelyhighdemandareasstillrequire100%waterproofandrapiddrainage,suchastheroof.Typicallyroofdrainagesysteminthedesign,constructionandmaintenancehasnotbeengivendueattention.Althoughthedrainagesysteminvestmentcostsaccountforonlyasmallportionofthetotalconstructioninvestment,butnotabletojudgethelosscausedbypoordesign.Therearetwodifferentformsofroofdrainagesystemdesignmethods,namelythetraditionalandsiphonmethod.Traditionalsystemsrelyonatmosphericpressurework,thedriveramaffectedsinkflowdepth.Therefore,theconventionalroofdrainagesystemsrequirearelativelylargediameterverticaldroptube,priortodischarge,alldevicesmustbeconnectedtothegroundwatercollectionpipenetwork.Incontrast,siphonicroofdrainagepipesystemsaregenerallydesignedtofullflow(turbulentflowmeansthatrequirelessexhaustpipe),whichwillformanegativepressure,thelargerthehigherflowrateandpressurehead.Typicallysiphonsystemrequireslessdownpipeworkundernegativepressuretothewaterdistributionnetworkcanmeanhigheraltitudework,therebyreducingtheamountofundergroundpipenetwork.Bothsystemsconsistsofthreeparts:theroof,rainwatercollectionpipes,pipenetwork.Alloftheseelementsareabletochangethewaterpressuredistributionsystem.Thissectionfocusesontheroleandperformanceofeachpart.Duetotheprincipleofsiphonsystemhasnotbeenwellunderstood,resultingargumentisrelativelysmall,thisarticlewillhighlightsiphonsystem.2.RoofTheroofisusuallydesignedbythearchitect,designerandnotbythedrainagedesign.Therearethreemainroof.2.1FlatroofFlatroofsareusedinindustrialbuildingslessrainfallregionsandcountries.Thisroofisnotcompletelyflat,butlowerthantheminimumroofslopemayrequire.Forexample,theUnitedKingdomrequiremaximumslopeof10°.Settingminimumslopeinordertoavoidanyunnecessarywater.Despitetheflatroofifitisnotproperlymaintainedwillhavemoreproblems,butitwillreducethedeadzonewithinthebuilding,andtheratioofslopingroofsinfavorofindoorair.2.2slopingroofsMostresidentialandcommercialbuildingsarepitchedroof,inclinedroofisthebiggestadvantagecanquicklydrain,therebyreducingleakage.Intemperateregions,weneedtoconsidercarryingroofsnowload.Onceitrains,rainfallthroughtheslopingroofscanbedeterminedbycalculation.Whenrainfalldatacanbeused,youcanusethekinematictheorytosolvesuchproblems.2.3greenroof(flatorinclined)Itcanproveroofistheoldestgreenroofs,includingrainfallcanreduceordisperseroofplantedwithplants.Itcanbeplantedwithtreesandshrubsroofgarden,itcanalsobeavegetatedrooflightcarpet.Whereinthelattertechniquehasbeenwidelyused.Someoftheseapplicationstendtofocusonaestheticrequirementsandareoftenusedingreendevelopment.Sincetheaestheticrequirementsandpressurerequirements,aswellasgreenroofsthermalinsulationfunction,reducetheheatislandeffect,silencereffect,extendthelifeoftheroof.GreenroofsinGermany,themostwidelyused,followedinNorthAmerica,buttoconsidertheimpactontheaesthetics.Germanyisbyfarthemostexperiencedcountriesinthe19thcenturyhavepracticalapplication,thenasanalternativetoreducetheriskoffiretarroofanoptioninurbanareas.Germanyiscurrentlythemainresearchquestiononthecultivationofotherissuestoconsidersmallercities.Astudyfrom1987to1989,wasfoundpackedwith70mmthickgreenroofcanbereducedby60%-80%ofheatloss.InaCanadianworkcomputermodelbasedontheroofindicatesthataslongasthesump,theareacanreach70%oftheroofareacanbereducedby60percentinoneyear,thesamemodelwasalsousedforartificialrainfall,whichtheresultsindicatethatrainfallinthecatchmentseasonhelpstodrainawayrainwater.However,noneofthesestudiesshowthatgreenroofscanplayausefulroleintherainfallseason,orhowhighcollectionefficiencyofwatersupply.TheUnitedStatesdidsometests,aslongasthegreenroofsregularwatering,canreduce65percentoftherunoffinarainfall.America'smostauthoritativegreenroofguidelinesbytheNewJerseystateenvironmentalagenciespromulgated.Themainprincipleistosolvethestructuralproblemsoflight,andhowcanthenormaldrainageaftertwoyears.Rainfallperiodisbasedontheprobabilityoffailureisdetermined.Thesystemistypicallybasedonrainfallduringrainstormstwominutes,twominutes,haveachoice.Althoughthismodelwillgetmoretraffic,butthereisnootherbetteralternative.Studieshaveshownthatthetraditionalmodelisappliedtostudygreenroofsarepremature.Lossfactorthantraditionalroofrecordsshouldbesmall,about98.7%.Peakflowwillbereduced,althoughnotpenetrate,thesurfaceroughnessbutalsohaveasignificantimpact.Concentratedrainfallthantwominutesforalongtime,especiallyforlargeroofareas,suchaspublicbuildings,commercialbuildings,industrialbuildings.Urbandrainagedesignshouldalsoconsiderotherfactors,foracomplexsystem,agreenroofinarainisnotenough.Waterflowdurationcurveshowsalongerthantraditionalsystems.Andtwoindependentandwillaffectbetweenispossible,whichrequiresamoreprecisetimeperiod.3.RainwaterCollectorBasicrequirementsrainwatercollectorisdesignedtobeabletoaccommodaterainfallrainstorms.Althoughitispossibletomakeaslightlyinclinedroofdrainagepurposes,butthenatureoftheconstructionindustryandbuildingsettlementwillbecomeflatroofTypically,thetankisplacedinahorizontal,sectionalviewofthewaterisoutwardlyinclined,whichtheroleofhydrostatic.3.1drainoutletAnalyzingrainwatercollectorhassufficientvolumeisthekeytothesumpoutletexternalsettingconditions.Alsoaffecttheflowrateintothestormwaterdrainagesystempiping,butalsoaffectthedepthofthewatercatchment.Althoughthedepthofthesumpwillnotbringanyparticularproblems,buttoodeepcancauseexcessivesump.Numerousstudiesinthe1980sshowedthattheflowofconventionalroofdrainagesystemoutletcanbedividedintotwocases.Itdependsonthesizeofthedepthandsizeoftheoutlet.Whenthewaterdepthislessthanhalfthediameteroftheoutlet,theflowofthefirsttype,andtheoutletoftheflowcanbecalculatedbyanappropriateequation;waterdepthincreases,exportsareslowlycloggingtheflowwillbecomeanotherformforms,atthesametime,theflowofexportscanbeobtainedthroughotherequations.Whileconventionalroofdrainagesystemsaredesignedtobefree-draining,butmaycauselimitationsencounteredinthedesignoftheflowisnotfree.Inthiscase,itwillrequireadditionaldepth.Siphonroofdrainagesystems,theoutletisdesignedtobesubmergedstream.Inthiscase,thedepthoftheoutletofthedecisionismorecomplicated,becausethedesignofthesumpdependsontheflow.Recentstudieshaveshownthatconventionalroofdrainagesystemsuseavarietyofnon-standardcatchment,theirdepthandheight,biggerthanthediameteroftheoutlet.Thiswilleventuallyresultinasiphoneffect.Foragivencatchment,theflowdependsonthestartingendofthedroptubediameter.Asimilarphenomenonhasalsobeenusedtostudythestandardcatchment,inthesecircumstances,onlylimitedsiphonactionoccurswithinrelativelyclosedistancefromtheexit.3.2tankflowclassificationInthecomplexflowsumpoutletflowclassification,canbeseenfromTable2a,theflowwillbeuniformlayering,regardlessofwhetherthesameinletflow.Table2band2cshow,exportdistributionwillgreatlyinfluencetheflow.Whentheoutletisnotafreejet,sumpoutletcomplexflowclassificationisdifficulttodescribe.Becauseeachcatchmenttankpressuresarelikelytobemerged.Forexample,thesiphontubesystemdesignpointisatnearfulljetoutletflowclassificationdependsontheenergylossofeachbranch.3.3hydrostaticsectionalSumpshapeofthewatersurfaceinthecanalcanbeclassifiedaccordingtotheflowequation.Inmostcases,alowflowratemeansthatthereislessfrictionloss,ifexportsarefreejet,thefrictionlossisnegligiblecross-sectionthroughthehydrostaticequation1todeterminethehorizontaldistance.WhereQ--flow(m3/s)T-surfacewidth(m)g-accelerationofgravity(m/s2)F-flowarea(m2)Equation1cannotbeignoredwhenthefrictionrequiredtocorrect(orverylongpipevelocityislarge),ornotafreejet.3.4ThecurrentdesignmethodsThepreviousdiscussionhashighlightedthemainfactorsthatshouldbeconsideredwithsinkdesign.However,withoutthehelpofacertainnumberofmodels,computinghydrostaticsectionalroofdrainagesystem,thevolumeofthesumpispossible.Thislargecommercialandmanufacturingindustry,isadevelopmentopportunity,youcanmergeseveralkilometersofwaterroutes.Thus,theconventionaldrainagesystemsumpdesignmethodsaremainlybasedonexperience,andassumethatexportsarefreejet.Sumplocationinthebuilding,itmaycausetheexampletofail.DifferentinterfacesumpExceptinthecasecitedabove,butalsoallowsdesignerstouseempiricaldata.3.5DigitalModelLargenumberofdigitalmodelscanbeusedtoaccuratelydescribetheflowofanyformofcatchmenttank,regardlessofwhethertheroofflowsstable.Anexampleofthismodelisacombinationofroofspacemodel.Thismodelenablesuserstoclassifydifferentaspectsofthedataindicated,includes:detailsoftherains,theroofsurfacedrainageandotherdetails.Kinematicshavealsobeenusedtostudyrainwatertanktoflowfromtheresearchcollection.Atypicalmethodisbasedonopensystemtosolveabasicproblemofspatialmobility.Thismodelautomaticallyresolvethesumpoutletflowsituation,butalsotodealwiththecaseoffreejetcanalsobesimulatedspacelimitedmobilityandsubmergeddischarge.Outputvalues??includedepthandflowrate.Currently,themodelisessentiallyjustavarietyofresearchtools,butalsothroughpracticalengineeringtest.However,weshouldfaceuptothevariousrolemodels.4pipesystemsgroupCompositionintheformandscopeofthetubegroupdeterminestheroofdrainagesystemreliesmainlyonthetraditionalsystemorsiphonaction.4.1TraditionalstormwatersystemsConventionalroofdrainagesystems,thegroundplaneisgenerallyverticalpipe-linenetwork,connectedtothesumpoutletandundergrounddrainagesystems,criticalsystemsaswellascompensatingtube.Itshouldbeemphasizedthattheanglebetweenthegroundandthecompensatingtubeislessthan10°.Capacityoftheentiresystemreliesmainlyontheoutlettubeinsteadofdown.Flowverticaltubeisusuallyfree-flowing,fullofonly33%,theefficiencydependsontheexcesslengthofthetube.Ifthedroptubelongenough(typicallygreaterthan5m),theremaybeanannularflow.Similarly,undernormalcircumstancesflowcompensationpipeisfree-flowing,fullofupto70%.Suchdesignedprocessbothforthedesign,variousequationscanalsobeused.4.2SiphonroofdrainagesystemIncontrastwiththetraditionaldrainagesystems,Siphonroofdrainagesystemreliesonairflowoutsidethesystem,andthetubeisfullpipeflowstream.Thedesignsareusuallymadeontheassumptionthatthedesignofheavyrain,thesystemcanquicklysiphondischargerainwater.Thisassumptionallowstheapplicationofhydrostaticsiphonsystemtheory.Oftenusedsteadyflowenergyequation.Whilethisapproachignoresthesmallamountofenergylossattheentrance,butaftertheexperimentshowedthattherearestillconducivetopracticaluse.However,steady-statedesignmethodsinthesiphonsystemisexposedtorainwhenthesystemdoesnotmeetthestandardrequirementsorchangesinrainfallintensityislargeisnotapplied.Inthefirstcase,therewillbesomemixingofairquality,annularflowoccurs.Theseproblemsarenotintegratedinthesystemwhenmoreserious.Becauseusuallydesignedrainsarecommon,itisclearnowdesignmethodologyovertimemaynotapplytosiphonsystem.Thisisamajordisadvantage,becausethedesignofthemainproblemisthenoiseandvibrationproblems.Despitethedisadvantagesofthepriordesignapproach,butalotoftheworld'sveryfewengineeringfailurereports.Whenafailureoccurs,mostlikelyforthefollowingreasons:AnincorrectunderstandingoftheoperationpointsSubstandardmaterialslistInstallationdefectsMaintenancemismanagementToovercomethesedisadvantages,wehaverecentlylaunchedaseriesofresearchprojects,todiscussthesiphonsystem,andthedevelopmentofdigitalmodels.Fromthisworkwelearnalot.Incontrastwithconventionaldesignmethodsofsomeassumptions,siphonsystemmainlyhasthefollowingaspects:1)non-flowsystemoffullflow2)levelsofcertainpipe-flowingfullpipeflow3)fullpipeflowdownstreampropagationthroughaverticalpipe,riser,etc.4)theinnertubeflowoccursovertheverticalsection,thesystemtoreducethepressure5)downwardtubeisfullpipeflow,therewillbeairlock6)appearscompletelysiphonactionuntilwellintotheairsystemislowerthanacertainlevelTable4acolumndataindicatethatbelowthedesignpoint,thesystemwillsiphonunstableflow,depthofthewatercollectingtankisinsufficienttomaintainthesiphonaction.Table4bshowthattheunsteadyflowinsiphonsystemwhenitwillappear.Table5liststhedataoutputofadigitalmodel.Itcanbeseenthatthemodelcanaccuratelydescribethesiphonaction,siphonandsteadystate,thedataalsoshowthatthemodelcanaccuratelydescribethecomplexsiphonaction.5ConclusionThisarticlehasillustratedthecriticalroofdrainagesystems,buttheseareoftenoverlookedintheurbandrainagesystemdesign.Thisarticlealsoshowsthatthedesignprocessisacomplexprocess,relymainlyontheperformanceofexports.Thefollowingconclusionsarebasedonthedesignsummedup:1)Rundependonthreeinteractingparts:theroof,sump,waterpipes2)Greenroofscanreducetrafficandbeautifythecity3)theexportperformanceofthesystemisessential4)siphondrainagesystemhaveagreateradvantageinlarge-scaleprojects,butmustbeconsideredhighmaintenancecosts5)DesignsiphondrainagesystemshouldconsideradditionalcapacityandoperationalissuesAlthoughthegreenroofisamoreattractiveoption,butthetraditionalroofofabuildinginthecountrywillcontinuetodominate.Greenroofswillbegraduallydeveloped,andgraduallybeenwidelyaccepted.Similarly,theroofdrainagesystemshowneffectivethatitwillcontinuetoplayahugeroleinthecommercialbuildingdrainagesystems.Roofdrainagesystemofthegreatestthreatsfromclimatechange,existingsystemstendtobenotsimplyaging;rainfallpatternsofchangewillresultininefficientoperation,self-cleaningratewillbereduced.Changesinwindspeedandtheroofwillalsoacceleratetheagingoftheroof,itisnecessarytocarryoutmaintenance.Takingintoaccounttheclimatechange,theincreaseinmaterials,roofcollectedrainwaterwillbemoreextensive.Currently,theamountofrainaroundtheglobeperpersonperday7-300litersintheUK,withanaverageconsumptionof145L/h/d,ofwhichonlyaboutoneliterisusedbypeople,about30percentofthetoilet,studyshowsIfwatershortage,rainwatercollectedontheroofofdevelopedanddevelopingcountriesarerecommendedapproach.屋頂排水設計性能的近期與遠期優勢最近十年見證了屋頂排水系統設計方面的巨大變化，特別的是，虹吸雨水排水系統已經得到逐步改善，并且有可能得到重點應用。發生這些變化的同時，城市排水系統設計已經發生了巨大的變化，因為適用范圍更廣的可持續發展城市排水系統設計，還有人們對于氣候變化帶來的洪水泛濫的更多關注。這篇文章的主要內容就是，如何設計屋頂雨水排水系統并使之有良好的運行性能。需要特別注意的是如何改掉已經形成的不良設計習慣，同時還要需要考慮屋頂排水系統的創新，如綠色屋頂和雨水收集系統。實際應用：在過去幾年，屋頂雨水排水系統的設計已經發生了巨大的變化。在大型建筑物上，虹吸雨水排水技術已經很常見，還有綠色屋頂由于其有利于綠色發展，正得到越來越多的應用。考慮到正在進行的研究，本文主要介紹如何有效地設計各種不同的屋頂雨水排水系統，并使其達到理想的設計效果。1.緒論在過去十年，城市與水排水系統設計已經想著廣為接受的可持續發展城市排水系統或者最優管理方向發展。設計這些系統主要原則是，既要有符合當地發展水平的質量，又要為投資者創造一定的經濟效益。這種原則已經引發了集水池發展方式新的變化。盡管這種裝置的應用正在逐漸減少，但是城市環境要求比較高的地區仍然要求100%防水且排水迅速，例如屋頂。通常屋頂排水系統在設計、建造和維護時并沒有受到應有的重視。盡管排水系統的投資費用只占建筑總投資的一小部分，但是，并不能據此來判斷設計不良帶來的損失。主要有兩種不同形式的屋頂排水系統設計方法，分別是傳統的和虹吸式方法。傳統的系統依靠大氣壓力工作，其驅動壓頭受到水槽流動深度的影響。因此傳統的屋頂排水系統需要一個直徑相當大的垂直下降管，在排放之前，所有的裝置都必須連接到地下水收集管網。與此相反，虹吸式屋頂排水系統通常設計成滿管流（紊流狀態意味著只需要較小的排氣管），從而會形成負壓，較大的壓頭和較大的流速。通常虹吸式系統需要較少的下降管，在負壓狀態下工作，意味著給水管網可以較高的高度上工作，從而減少地下管網量。兩種系統都由三部分組成：屋頂，雨水收集管道，系統管網。所有這些部分都能夠改變系統的水壓分布。這部分主要關注各部分的作用和性能。由于虹吸系統的工作原理并沒有得到很好的理解，得到的論證比較少，本文將會重點介紹虹吸系統。2.屋頂通常屋頂是由建筑師設計的，而不是由排水設計者設計的。主要有三種屋頂。2.1平屋頂平屋頂主要應用在降雨量比較少的地區和發達國家的工業建筑。這種屋頂并不完全是平的，而是低于所規定的屋頂最小坡度。例如，英國規定最大坡度為10°。設定最小坡度是為了避免任何不必要的積水。盡管平屋頂如果得不到正確的維護會產生較多的問題，但它會減少建筑物內的死區，且比斜屋頂有利于室內氣流組織。2.2斜屋頂大多數居住建筑和商業建筑都是斜屋頂，斜屋頂最大的優點是可以迅速排水，從而可以減少漏水。在溫帶地區，不需要考慮屋頂承載的降雪載重。一旦下雨，斜屋頂通過的降雨量就可以通過計算確定。當有降雨資料可以利用時，可以使用運動學理論來解決這類問題。2.3綠色屋頂（平的或者是斜的）可以證明最老的屋頂就是綠色屋頂，它包括可以減少或驅散降雨的種有植物的屋頂。它可以是種有樹和灌木的屋頂花園，也可以是長有植被的輕型屋頂地毯。其中后一種技術已經得到廣泛應用。其中一些應用趨向于側重美學要求并經常應用于綠色發展。由于審美要求和水壓要求，綠色屋頂還有熱絕緣的功能，減少熱島效應，有消聲作用，延長屋頂的使用壽命。綠色屋頂在德國應用最為廣泛，在北美地區次之，但是要考慮美學上的影響。德國是目前為止最有經驗的國家，早在19世紀就有實際應用，當時作為在城市地區替代焦油屋頂降低火災危險的一種選擇。目前德國主要研究放在種植問題上，對城市的其它問題考慮較少。從1987年到1989年的一項研究工作，發現裝有70毫米厚的綠色屋頂可以減少60%-80%的熱損失。在加拿大的一項基于電腦模型的工作，表明在屋頂只要集水器是、的面積能夠達到屋頂面積的70%，在一年內就能減少60%，同樣的模型也被用于人工降雨，其結果都表明集水器在降雨季有助于雨水排走。但是這些研究都沒有表明綠色屋頂在降雨季可以發揮多大的作用，或者給水管的收集效率有多高。美國做了一些測驗，只要對綠色屋頂經常的澆灌，就可以在一次降雨中減少65%的徑流量。美國最有權威的綠色屋頂指導原則是由新澤西州環保部門頒布的。這項原則主要是解決輕型結構問題，以及如何在兩年之后還能正常的排水。降雨周期是根據是根據失敗的概率決定的。通常的系統是根據暴雨期間兩分鐘的降雨量，這兩分鐘是有選擇的。盡管這種模型會得到更高的流量，但是沒有其他更好的替代方法。研究表明，傳統模型應用于綠色屋頂的研究是是不成熟的。流失量系數比傳統屋頂記錄的要小，大約為98.7%.峰值流量也會減少，雖然沒有滲透，但是表面粗糙度也會產生顯著的影響。集中降雨的時間要比兩分鐘要長，特別是對面積較大的屋頂，如公共建筑、商業建筑、工業建筑。城市排水設計還要考慮其他一些因素，對于一個復雜的系統來說，一個綠色屋頂在一場降雨中是不夠的。流量水位曲線顯示的持續期要比傳統系統長。并且兩場獨立的將與之間的影響也是有可能的，這需要更加精確的時間周期。3.雨水收集器雨水收集器的基本要求是要能夠容納設計暴雨時的降雨量。盡管通常情況下可以通過讓屋頂稍微傾斜來達到排水的目的，但是建筑工業的性質及建筑物的沉降都會式屋頂變得平坦，在水平放置的水槽中，水的剖面是向外傾斜的，這是流體靜力學的作用。3.1排水溝出口的深度判斷雨水收集器是否具有足夠容積的關鍵是集水器外部出口的設置情況。還會影響流入雨水排水系統管道的流速，還會影響集水器的積水深度。盡管集水器的深度不會帶來什么特別的問題，但是過深會導致集水器過高。20世紀80年代的大量研究表明，傳統屋頂排水系統的出水口的流動情況可以分為兩種情況。這取決于水深與出口尺寸的大小。當水深小于出口直徑的一半時，流動情況是第一種類型，并且出口的流動情況可以通過合適的方程計算出；隨著水深的增加，出口會被慢慢堵塞，流動形式會變成另一種形式，同時，出口的流動情況可以通過其他方程得出。盡管傳統屋頂排水系統被設計成可以自由排水，但是設計中遇到限制可能會使出流不是自由的。在這種情況下，就會需要額外的深度。在虹吸式屋頂排水系統中，出水口被設計成淹沒出流，。在這種情況下，決定出水口的深度比較復雜的，因為集水器的設計取決于流動情況。近期的研究表明，傳統的屋頂雨水排水系統使用各種非標準的集水器，它們的深度和高度，都要比出口的直徑大。這最終會造成虹吸作用。對于一個給定的集水器，始端的流動情況取決于下降管的直徑。類似的現象也被用于研究標準的集水器，在這些情況下，受限的虹吸作用只發生在離出口比較近的距離內。3.2槽內的流動分類在集水槽復雜流動出口的流動分類中，可以從表2a中看出，流動會出現均勻的分層，而不管入口的流動情況是否相同。表2b和2c表明，出口的分布會極大的影響流動情況。當出口不是自由射流時，集水槽中復雜出口的流動情況分類是很