基于遥感与CFD仿真的城市热环境研究——以武汉市夏季为例

华中科技大学博士学位论文基于遥感与CFD仿真的城市热环境研究——以武汉市夏季为例姓名：李鹍申请学位级别：博士专业：建筑设计及其理论指导教师：孙九林;余庄20080404IRSRemoteSensingCFDComputationalFluidDynamicsRSCFDCFD123CFDCFDII4CFD5CFDCFDCFD6CFDCFDCFDCFDIIIAbstractInhot-summerandcold-winterzoneinourcountry,Humaninquitesomecitiesisconfrontingthechallengeoflivingdifficultyduetothedramaticallychangingclimate.Relatedproblemsincludinglivingsituationsespeciallyinsummerandheatenvironmentsarebecomingafocus.Theproblemsofcityheatenvironmentincludecityclimate,cityplanning,cityunderlyingsurfaceandsoonandarerelatedtomultidisciplinaryfields.BasingonWuhan,atypicalcityinhot-summerandcold-winterzone,theresearchpresentsthedigittechnologiesonremotesensingRSandcomputationalfluiddynamicsCFDandadetailwasshownintherunningstatusoftheheatenvironmentsandstructureofheatislands.Otheraspectsincludinganalyzingthestructureofheatislandsandseekingforcorrespondingmeasuresinurbanplanningarealsodisplayed.TheRStechnologyshowstheadvantagesofacomprehensiveandperiodicalobservationandthethermo-infraredofRSimageusingtoinversethesurfacetemperature,theevapotranspirationandthevegetationindex,aswellastoconducttheenvironmentanalysisinaccordancewiththepropertyandstructureofunderlyingsurfaces.Furthermore,theRStechnologyiscapableofreversingtheparametersandresultsfortheCFDtechnology.TheCFDhastheadvantageofconductingfluidanalysis.Itcanpresenttherelationshipofadistinctboundarylayerinthecityatmosphere,theheatenvironmentandtherunningstatusofheatislandsusingthesimulationofwind.Additionally,itcanevaluatethedesignoftheconceptionandoptimizationviasimulation.Combingbothtechnologiesonstudyingheatenvironmentswouldsupportwithoneanotherandthusisatightresearchsystem.Basingonsuchathought,themainworkofthedissertationisshowasfollows.1Firstly,thederivation,backgroundanddefinitionoftheheatenvironmentsarestudied,followedbysummarizingrelevantliteratures.Itcanbeconcludedthatsucharesearchhasitsunique.Thoughtherehavebeensomedigitizationmethodsavailable,somearelimitedtothesinglesubjectandthusarelackofcomprehensivestudieswithmultidisciplinarybackgroundsandcomprehensivetechnologies.ThisisoneofflashpointsIVinthisdissertation.2Quitesomeissuesrelatingtotheheatenvironmentarementioned,suchastheclimate,atmosphericboundary-layer,underlyingsurfaceandtheindexofheatenvironments.Theheatenvironmentcanbederivedfromtheboundarylayerandisinfluencedbytheclimate,underlyingsurfaceandsoon.Wearetryingtofindtherelationshipamongtheheatenvironment,cityclimateandtheunderlyingsurfaceusingasystematicanalysisandcorrespondinglyestablishingafoundationforthesubsequentdigitization.3Adigitizationmethodfortheresearchofcityenvironmentisestablished.SuchamethodcombinestheRSwiththeCFDexpectforthedatacollection.TheRSisusedtostudytheheatenvironmentbyinversingtheland-surfacetemperatureandtheevapotranspiration,andbycombiningunderlyingsurface’sparametersintoresearch.Meanwhile,theCFDisusedtosimulatetheheatenvironmentbysettingupadigitalandfluidmodel.4Basingonthedigitizationmethod,theRS-basedheat-environmentresearchisconducted.SuchstudiesincludethesestepssuchasthechoiceofRSimages,datapretreatmentandland-surfacetemperatureinversion.Therelationbetweenheatislandandunderlyingsurfacesarediscussed,includingtheunderlying-surfaceindexandextraction.Moreover,thestructureoftheheatislandandthetypicalsurfacearealsopresentedusingWuhanasthereference.Asaresult,therearecompleteresearchesonvariousstagesandcitieswhichcoverinhot-summerandcold-winterzone.Theevapotranspirationofthenaturalsurfaceisalsocarriedout.Althoughtheevapotranspirationcannotdirectlyreflecttheheatsituation,itabsorbsheatandthusimprovestheheatenvironment.Thus,suchamethodcanbeusedtoincreasetheaccuracyoftheCFDsimulation.Themodelofacquiringtheevapotranspiration,therunningprocessandrelationshipwiththesurfacetemperatureisdiscussed.5Basedonrelatedconclusions,thestudyexaminesboundaryconditionsettingsofCFDsimulation,whichisthekeyoftheCFDsimulation.Thesettingoftraditionalboundaryconditionsissimplebutislackofprecision.Toovercomesuchdrawbacks,wehavemodifiedthesettingbyusingtheRStechnology,thusmakingthesimulationbettermatchingtothestructureandcharacteristicofheatislands.V6UsingthedigitalmodelreversedbytheRStechnology,thestudyalsosurveystheheatsituation,therelationbetweenthewaterbodyandtheheatenvironments,andtheventilationpanelbasingonthestudyresultsofflowinginthemotionofatmosphere.TheCFDisfoundsuitablefortheproblemwellintermsofflowingandthusisanewandefficientwayregardingtheanalysisofthewindenvironment,thetemperaturefield,thelivingenvironmentandtheheat-islandcondition.Thestudyoftheheatsituationbasingonthespatialinformationtechnologyisefficientincityenvironmentalmanagementandcontrol.Itisanimportantfieldincityplanningandenvironmentalsciences.TheRSandtheCFDtechnologiesusinginthestudyarelessusedforrealplanningprojects.Inthepreconditionofscientificplanningmethodsmentionedgreatlybylocalgovernment,promotingthisresearchmethodandcombingitwithrealplanningprojectappeartobemeaning.KeywordsHot-summerandCold-winterzoneWuhancityCityheatenvironmentRemoteSensingComputationalFluidDynamicsD