A-0-水文水動力基本原理

FundamentalsandTheoryofHydraulicModelling

水力模型的基本原理和理論JuanGutierrez(古霆歡)&竇秋萍Whydoweneeddrainagestudies?IncreasingPopulationMajorDevelopmentsRecentFloodingEventsOngoingClimateChangeHigherExpectations2023/2/5Whatisamodel?Model?RepresentationofrealityWithaclearobjectiveFloodassessmentWaterQualityFloodforecastingsystemMasterPlanLocalfloodriskassestmentetc…05/02/2023Whatisamodel?Model?RepresentationofrealityWithaclearobjectiveFloodassessmentWaterQualityFloodforecastingsystemMasterPlanLocalfloodriskassestmentetc…05/02/2023Fitforpurpose!!!Whydoingmodelling?05/02/2023Moreadvancethantraditionalmethods(rationalmethod)AllowsyouanalysisofdifferentscenariosTraditionalmethods:Rationalmethod05/02/2023Insertfooterforallslideswith'Insert-Header&Footer'Page6CatchmentoutfallDoesnotconsiderwhathappensdownstream! ItdoesnottakeintoaccountstoragesolutionsItdoesnottakeintoaccountbackwatereffectsDisadvantages!!!Qup>>QrpVu>>VrRationalMethodQp=CIA/360Qp=peakrunoff[m3/s]C=Runoffcoefficient(between0&1)I=Rainfallintensity(constant)[mm/hr]A=Catchmentarea[Ha]360=conversionfactor7Catchmentarea=30Hectares匯水區(qū)面積=30公頃Rainfallintensity=60mm/hr降雨強度=60mm/hLanduse=mediumdensityresidentialarea（C=0.9）土地利用=中密度住宅區(qū)域（C=0.9）Q=CiA

peakflowonly!峰值流量Q=4.5m3/s8RationalMethod–Example推理法-示例

Whydoingmodelling?:

Analysisofdifferentscenarios

ModelExistingscenarioHistoricaleventsDesignevents(30,50,100,1000yrreturnperiod)FuturescenarioNewfloodingschemesbeforeconstructionNewlanduses05/02/2023TherecordsalsomostlyreferstomeasurementstakeninONEpointWhydoingmodelling?Whydoingmodelling?ModelExistingscenarioHistoricaleventsDesignevents(30,50,100,1000yrreturnperiod)FuturescenarioNewfloodingschemesbeforeconstructionNewlanduses05/02/2023ConceptsandPrinciplesofHydrology

水力學概念和原則HydrologicalCycle

水循環(huán)13Thegeneralconceptofthehydrologicalcycle

水循環(huán)的一般概念

Thehydrologicalcycleisaclosedsysteminthatwatercirculationinthesystemremainswithinthesystem.

Thewholecycleisdrivenbytheexcessofincomingsolarradiationoveroutgoingradiation.Thecycleconsistsofthesesubsystems:(i)atmospheric,(ii)surfacerunoff,(iii)sub-surface14水文循環(huán)是個封閉的循環(huán)系統(tǒng)，無論水以什么樣形式存在，都仍然在該系統(tǒng)中。整個水文循環(huán)系統(tǒng)在太陽輻射的驅動力下進行。該循環(huán)由以下子系統(tǒng)組成：大氣循環(huán)

地表徑流(iii)地下循環(huán)ICM包括的最基本的計算引擎包括Hydrology1DRivers(nonprismatic)1DPipes(prismatic)Overlandflows2D2023/2/5Hydrological&HydraulicModels

水文水力模型Hydrologicmodel水文模型

Rainfall-runoffmodelconvertsrainfalltocatchmentrunoff降雨徑流模型將降轉換為匯水區(qū)徑流Input:rainfallhyetograph輸入：降雨過程線Output:flowhydrograph輸出：流量過程線Hydraulicmodel

水力模型simulatestheflowbehaviourintheriver/pipe模擬河道/管道內的流動狀態(tài)Inputs:flowhydrograph&downstreamwater-level輸入：流量過程線和下游水位Outputs:water-levelsandflows輸出：水位和流量16Subcatchment

匯水區(qū)Thecatchmentoutlet17匯水區(qū)排放口水文模型Hydrology1DRivers(nonprismatic)1DPipes(prismatic)Overlandflows2D2023/2/5Rainfall-RunoffModels

降雨徑流模型Lossmodels(runoffvolumemodels)損失模型（徑流模型）Routingmodel匯流模型19SomeRainfall-RunoffModels

一些降雨徑流模型Eventbasedrainfallrunoffmodels事件降雨徑流模型Formodellingonerainfallevent模擬單一降雨事件Normally24hourevent一般為24小時降雨事件Eg:designevent例如：設計降雨事件Continuousrainfallrunoffmodel持續(xù)降雨徑流模型Formodellinglong-term模擬長期事件Oneseasontomanyyears一個季度甚至很多年Foryieldanalysis產水量分析20SomeRainfall-RunoffModels

一些降雨徑流模型Eventbasedrainfallrunoffmodels事件降雨徑流模型RationalMethod(peakflowonly)推理計算法（僅考慮峰值流量）ModifiedRational(Hydrograph)修正推理計算法（水位過程線）Time-AreaMethod時間-面積法UnitHydrographMethods單位過程線法Continuousrainfallrunoffmodel持續(xù)降雨徑流模型PDM(probabilitydistributedmodel)PDM（概率分布模型）21

Hydrology

水文Page22Excessrainfall凈雨量RainfallDischargePeak峰值RisingLimb漲水段Fallinglimb退水段Baseflow基流SurfaceRunoff徑流Losses;損失：Toevapo-transpiration蒸發(fā)Togroundwater補充地下水Discharge(m3/s)Time(minutes)Discharge(m3/s)Time(minutes)匯水區(qū)出口的流量曲線23

Hydrology

水文RationalMethod

推理法Qp=CIA/360Qp=peakrunoff[m3/s]峰值流量C=Runoffcoefficient(between0&1)徑流系數(shù)I=Rainfallintensity(constant)[mm/hr]降雨強度A=Catchmentarea[Ha]匯水區(qū)面積360=conversionfactor換算系數(shù)24Catchmentarea=30Hectares匯水區(qū)面積=30公頃Rainfallintensity=60mm/hr降雨強度=60mm/hLanduse=mediumdensityresidentialarea（C=0.9）土地利用=中密度住宅區(qū)域（C=0.9）Q=CiA

peakflowonly!峰值流量Q=4.5m3/s25RationalMethod–Example推理法-示例

Rainfall-RunoffModels

降雨徑流模型Lossmodels(runoffvolumemodels)損失模型（徑流模型）Routingmodel匯流模型2627SCSCurveNumber

SCS曲線數(shù)28CNSource:AGuidetoHydrologicAnalysisUsingSCSMethods,byRichardH.McCuenTime-AreaMethod

時間-面積法29降雨強度柱狀圖匯水區(qū)等時線圖時間-面積曲線徑流過程線Time-AreaMethod

時間-面積法Step(1):Delineatesubcatchmentsbasedontheisochrones基于等時線描繪子匯水區(qū)Step(2):CalculatedesignrainfallIforthewholecatchment整個匯水區(qū)的計算設計降雨Step(3):Calculateordinatesofthehydrograph計算水位曲線的縱坐標值30CalculationoftheTimeAreaMethod

時間面積法計算ABCDEFGHIJKTimeRainfallLossesERTime-AreaCurveRunoffGeneratedbytheEffectiveRainfall(inmm)Hydrograph(min)(mm)(mm)(mm)(m2)9.92.3(m3/s)00.00.00.000.000.003270001.480.001.48615.90.015.9500001.262.390.003.6599.10.09.1690001.042.031.370.004.44126.80.06.8850000.881.681.161.020.004.75152.30.02.31000000.821.420.960.870.344.41180.001.330.810.720.293.15210.000.760.610.241.61240.000.570.200.77270.000.190.19300.000.00Note:ER-EffectiveRainfall31

Hydrology

水文Page32Excessrainfall凈雨量RainfallDischargePeak峰值RisingLimb漲水段Fallinglimb退水段Baseflow基流SurfaceRunoff徑流Losses;損失：Toevapo-transpiration蒸發(fā)Togroundwater補充地下水UnitHydrographMethod

單位過程線法SCSUnitHydrograph33UnitHydrograph–Superposition

單位過程線-疊加Page34ExcessrainfallTime123123DischargeTimeRainfall:Statistics

降雨：統(tǒng)計降雨35IDF(intensity-duration-frequency)強度-持續(xù)時間-頻率DDF(depth-duration-frequency)深度-持續(xù)時間-頻率Rainfall:DesignStorm

降雨：設計降雨36Rainfall:DesignStorm

降雨：設計降雨37ProbabilisticDistributionModel

概率分布模型

TheProbabilityDistributedModel(PDM)isarainfall-runoffmodelbasedonprobabilitydistributedmoisturestoresandtranslationofrunoffanddrainageviaroutingstores.概率分布模型(PDM)是一種基于降雨存儲分布、徑流轉移和排水行洪路徑的降雨徑流模型。38ICM中水動力模型Hydrology1DRivers(nonprismatic)1DPipes(prismatic)Overlandflows2D2023/2/5Page40FlowClassifications流態(tài)分類FlowStates流態(tài)Sub-critical緩流Slowanddeep:lowkineticenergySuper-critical湍流Fastandshallow:highkineticenergyCritical臨界流

Uniquerelationbetweenvelocityanddepth,y(=A/B)Vc=(gy)1/242慢并且深：運動能量低快并且淺：運動能量低流速和深度關系唯一，y=A/BFlowStates流態(tài)Sub-critical緩流y>ycV<(gy)1/2Super-critical湍流y<ycV>(gy)1/2Criticaldepthycwhen臨界流

Vc=V=(gyc)1/243Froudenumber弗勞德數(shù)Froudenumber弗勞德數(shù)

Fr=V/(gy)1/2whereVisvelocity(m/s),V—流速yisdepth(m)y—水深gisaccelerationduetogravity(m/s2)g—重力加速度Fr<1 subcriticalflow緩流Fr=1 criticalflow臨界流Fr>1 supercriticalflow湍流44SpecificEnergy比能SpecificEnergyE=y+V2/2g比能方程GraphofEforafixeddischargeq固定排放系數(shù)的E曲線45Normalandcriticaldepths

一般深度和臨界深度Fr<1Fr>1Fr=1Criticaldepth臨界深度Subcriticalyn>yc緩流Supercriticalyn<yc

湍流46Transition-HydraulicJump

過渡——水躍47Flowprofiles流量剖面Gradually&RapidlyVariedFlow漸變流和急變流Non-UniformFlowProfiles

非均勻流剖面49WaterLevelDistanceLowTideTidallyaffectedzoneFluvialzoneHighTideTidalRiverFloodProfiles

潮汐洪水剖面50M1M2河道區(qū)潮汐影響區(qū)高潮低潮51Gradually&RapidlyVaryingFlow漸變流和急變流

Continuityequation

MomentumequationLocalaccelerationConvectiveaccelerationPressureForceGravityForceFrictionForceKinematicwaveDiffusionwaveDynamicwave52St.VenantEquations圣維南方程連續(xù)性方程

動量方程St.VenantEquations

圣維南方程Underlyingbasisfor1Dmodels一維模型的根基Assumptions:假定：Graduallyvaryingflow;漸變流；Verticalaccelerationsnegligible忽略垂直加速度Hydrostaticpressure液體靜壓力Mildbedslope(lessthan10deg);平緩的河床坡度（小于10度）InfoWorkscanhandlegreaterslopesInfoWorks能夠處理較大坡度Fixedbed固定床1Dflow;一維流Water-surfaceishorizontal水面水平Velocitiesarearea-averaged速度為面積平均速度Manning’sEqn/CW(forsteadystateflow)isapplicable曼寧方程/CW（穩(wěn)態(tài)流）適用53St.VenantEquations

圣維南方程Structures結構OftenRapidlyVaryingFlow急變流ReplaceMomentumEqnwithEnergyEqn能量方程代替動量方程Junctions交匯處Compatibilityofwater-level水位匹配Flowprofiles流量剖面Applicableforuniformflowandnon-uniformflow均勻流和非均勻流均適用ApplicableforM1(backwater),M2(drawdown),S1&S2M1（回水）、M2（跌水）、S1和S2均適用。Applicableforsteady-stateflowandnon-steady-stateflow穩(wěn)態(tài)流和非穩(wěn)態(tài)流均適用Applicableforsuperandsub-critical湍流和緩流均適用Criticalflow:useQ(h)臨界流：用Q(h)Reproducesloopedratingcurve重新生成繩套曲線54Stage(m)Discharge(m3/s)RisingRecessionStage(m)Discharge(m3/s)RisingRecessionStage(m)Discharge(m3/s)RisingRecessionStage(m)Discharge(m3/s)RisingRecession繩套曲線衰退衰退上漲Uniformflowratingcurve(Kinematicwaveandmostlumpedroutingmodels)Loopratingcurve(Dynamicanddiffusionwavemodels)55St.VenantEquations

圣維南方程Boundaryconditions;邊界條件Upstream上游Q(t)

-usual(i.e.hydrologicalmodel)H(t) -careful!Ratingcurve,Q(H) -never!!Downstream下游Q(t) -careful!H(t) -usualRatingcurve,Q(H) -usualInternalconditions內部條件Drowned,Q(Hu/s,Hd/s)Criticalflow,Q(Hu/s)56Hydraulicstructures

水工構筑物HydraulicStructures;水工建筑物OftenRapidlyVaryingFlow急變流ReplaceMomentumEqnwithEnergyEqn用能量方程代替動量方程Examples;舉例Bridge橋Weir堰Gate閘門Culvert涵洞Siphon虹吸Barrage攔河壩Pump泵57St.VenantEquations

圣維南方程PartialDifferentialEquations(PDEs)偏微分方程Cannotbesolvedanalytically不能分解解Mustbesolvedbyapproximatemethods必須近似解Continuous連續(xù)的butsolvedatdiscretepointsinspaceandtime但是在時間和空間的散點上解Solvedbyapproximatemethods;用近似法解Finitedifferences:1DsolutiontechniqueinInfoWorks

—有限差：InfoWorks的一維解法581Dvs2D592DHydaulics1Dengineforpipednetworksandrivernetworks管網和河道的一維引擎2Dengineforfloodplainandabove-groundsystems(overlandflow)&non-1Dflowaroundstructures漫灘區(qū)、地面以上系統(tǒng)和構筑物內的非一維流2DFlowEquations

二維流量方程Basedontheshallowwaterequations,iethedepth-averagedversiontheNavier–StokesEqns淺水方程，即納維斯-斯托克斯方程602DFlowSolverInfoWorks2Dcomponent;InfoWorks的2D組件Solvesconservationofmass&momentum質量守恒和動量守恒Finite-volume,Explicitsolver,Unstructuredmesh有限體積，非結構網格thesolverisfullyconservativeandshock-capturing,soparticularlysuitableforthesimulationofrapidlyvariedflows.解法非常保守，適合急變流的模擬61Prismaticandnotprismaticlinks

柱狀連接和非柱狀連接05/02/2023Prismatic柱狀NonPrismatic非柱狀Prismaticandnotprismaticlinks

柱狀連接和非柱狀連接05/02/20233Dview3D視圖Prismatic柱狀Planview平面視圖NonPrismatic非柱狀River1D-2Dconnection

河道1D-2D連接05/02/2023Advantagesofunstructuredmesh

非結構網格的特點Page65Page66Test4:Circulardam-breakwave-initiallydrybed

潰壩洪水波-干涸河床Page67InfoWorks2DNote:Distancebetweenconcentricallygreycircles=500mPage68Aregularmeshsoftware

常規(guī)網格軟件Depth(m)Note:Distancebetweenconcentricallygreycircles=500m,Dryweatherflows

Flowsurvey(3or4days)Pumpingstation/WWTWdataDiurnalcycles,etc.StormeventsFlowsurvey(3events)Pumpingstation/WWTWdataTide/riverlevelsModelVerificationIssuestoconsiderAssessmentofflowsurveydataAllocationoffoulflows:locationsflowratesdiurnalflowprofilesInfiltration/baseflows/tidalinflowAllocationofimpermeableareasSoil/runoffparametersInfiltrationmoduleModellingofancillariesItemstocompare:FlowratesVelocitiesDepthsVolumesHistoricverificationRainfalldataFloodingrecordsPumpingstation/WWTWdataCSOspillsTide/riverlevelsModelVerificationReviewReporting:ModelBuild/VerificationReportTobebasedonGDSDSreporting(Phase2)CommentsonsourcesofdataAssetsurveyImpermeableareasurveyCCTVsurveyFlowsurvey–includingmonitorperformanceModelbuildprocessUseofavailabledataAncillaries–pumpingstations,CSOs,etc.ModelverificationprocessVerificationresultsGraphicalcomparisonsTabulardataDiscussion–keyissues/modelsuitabilityHydraulicAssessmentDesignStorm–existingmodelFlood&surchargefrequenciesSyntheticDesignStormsLocalrainfallparametersRangeofdurationsReturnperiodsDesignStorm–futuremodelUpdatingofmodelforfutureFlood&surchargefrequenciesTimeSeries–existingmodelCSOspillfrequencies&volumesFutureModelUpdatesFuturedevelopments&populationsProposeddrainageimprovementsChangestopopulation,waterusage,tradeflows,etc.Climatechange(seeGDSDSpolicy)HistoricalRainfallSeriesChoiceofsuitablerainfalldata-synthesisedifnecessary(e.g.TSRSim)TimeSeries–futuremodelUpdatingofmodelforfutureCSOspillfrequenciesHydraulicAssessmentReviewHydraulicAssessmentStagesReporting:HydraulicAssessmentReportDigitalplans–usingMapInfoTobebasedonGDSDSreporting(Phase2/Phase3)ExistingandfutureperformancesFlooding&surcharging(X-Xdiagrams)CSOperformanceSpillfrequenciesSpillvolumesPFFsatspillsFormulaAflowsPlanofExistingPerformanceProposedImprovementOptionsCloseliaisonbetweenTobin&HRWteamsImprovementslikelytoinclude:Localrepairs/rehabilitation(sewers&manholes)UpsizingofsewersNewsewersSurfacewaterseparationStorageprovisionCSOimprovementsBasedonvariousperformancedeficiencies