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简介:纸介绍一个词法模型和它的申请的发展给试验性的模型河。模型考虑隧道移植的关键进程,包括床变丑,河岸失败并且弄湿并且弄干。在拐弯的第二等的流动在侧面的沉积运输起一个重要作用,它进一步影响隧道移植。一个新公式被导出预言近床的第二等的流动速度,速度的大小在被连接到侧面的水水平坡度。因为仅仅非连贯的沉积在当前的学习被考虑,河岸失败基于休息的沉没角度的概念被建模。弄湿并且弄干的过程用一个存在方法被建模。在为各种各样的分泌物的数字模型预言和试验性的观察之间的比较被做了。模型预言隧道平面形状和代表性的形状与实验室观察通常同意很好,这被发现。情形分析也被执行在隧道迁居过程上调查第二等的流动的影响。它证明如果第二等的流动的效果被忽略,在侧面的方向的隧道尺寸将严重被低估。
简介:Theresultsofmathematicalmodellingofunsteadyflowconditionscoupledwithspecificsedimenttransportrelationsarepresentedhere.SimultaneoussolutionsofthedeSaintVenantequationswiththreedifferenttransportrelations,namelytheEngelund-Hansenequation,Grafequation,andanempiricalequationarepresented.TheresultsobtainedwerecomparedwiththosefromtheFluvial-12programunderthesameinputconditionsandreasonablecorrelationwasobserved.Theadvantagesofthecoupledmethodforsimultaneoussolutionoftheequationscompriseahigherdegreeofaccuracy,thepossibilityofintroductionofanydesiredtransportequationintothemodelandthepossibilityofintroducinganyboundaryconditionsintothemodelalongsideacompleteunsteadyflowmodelling.
简介:Algalbloom,knownasredtide,hasoccurredfrequentlyintheBohaiSeainrecentdecadescausinggreateconomiclossestofisheriesaswellashavingsignificantadverseimpactontheenvironment.A3-DEco-Hydraulicmodelisdevelopedtosimulatetheexplosivepropagationofdiatomanddinoflagellateasafunctionoftheconcentrationofvariousnutrients,riverinflow,tide,temperature,wind,sunshineandrainfall.Themodelisintendedtoanswerthequestionsofhowthe1998BohaiSearedtideoccurred,andtoinvestigatehowenvironmentalfactors,suchastemperature,wind,rainfall,solarradiance,seacurrentsandnutrients,affectthealgalbloomprocess.Theparametersemployedinthemodelarecalibratedwiththedatacollectedintheperiods1982-1983and1992-1993.Resultsfromthemodelindicatethateutrophicationoftheseawateristhebasicconditionforalgalbloom,andthatthe1998redtidewastriggeredbytheabnormalwarmweatherinAugustandSeptember.
简介:当前的学习为词法床变化的预言集中于一个三维的数字模型的申请。在一座水库的沉积免职在10-year-flood期间被调查,模拟的结果被验证,数据源于物理模型研究。因为在原型的小谷物尺寸,合成成粒在物理模型被使用。数字计算领域是物理模型的繁殖,包括谷物尺寸和粒子的密度,以便保证相似性。CFD代码SSIIM,它解决跑方程在三尺寸,被用于模拟。在SSIIM的沉积运输被划分成推迟的沉积运输,由解决传送对流散开方程,和水流带来的碎石运输计算了,由一个实验公式计算。数字模拟的结果对应于很好物理模型学习的结果。模仿的地点和在水库的沉积免职的模式是在物理模型的观察分发的一个精确代表。
简介:Afixedlink(tunnelandbridge,intotal16km)wasconstructedbetweenSwedenandDenmarkduring1995-2000.Aspartofthework,approximately16milliontonnesofseabedmaterials(limestoneandclaytill)weredredged,andabout0.6milliontonnesofthesewerespilledinthewater.Modellingofthespreadingandsedimentationofthespilledsedimentstookplaceaspartoftheenvironmentalmonitoringoftheconstructionactivities.Inordertoverifytheresultsofthenumericalmodellingofsedimentspreadingandsedimentation,anewmethodwiththepurposeofdistinguishingbetweenthespilledsedimentsandthenaturallyoccurringsedimentswasdeveloped.Becausethespilledsedimentstendtoaccumulateattheseabedinareaswithnaturalsedimentsofthesamesize,itisdifficulttoseparatethesebasedpurelyonthephysicalproperties.Thenewmethodisbasedonthegeo-chemicaldifferencesbetweenthenaturalsedimentintheareaandthespill.ThebasicpropertiesusedarethehighercontentofcalciumcarbonatematerialinthespillascomparedtothenaturalsedimentsandthehigherCa/Srratiointhespillcomparedtoshellfragmentsdominatingthenaturalcalciumcarbonatedepositioninthearea.ThereasonforthesedifferencesisthatcarbonatederivedfromrecentshelldebriscanbediscriminatedfromDanienlimestone,whichisthematerialinwhichthemajorityofthedredgingtookplace,onthebasisoftheCa/Srratiobeing488inDanienLimestoneand237inshelldebris.Thegeochemicalrecognitionoftheoriginofthesedimentsprovedusefulinseparatingthespilledfromthenaturallyoccurringsediments.Withoutthisseparation,validationofthemodellingofaccumulationofspilledsedimentswouldnothavebeenpossible.Themethodhasgeneralvalidityandcanbeusedinmanysituationswheretheoriginoragivensedimentissought.
简介:Two-dimensionalhydrodynamicsimulationfortheYangtzeEstuaryisperformedbyusingtheDelft3Dmodeladoptingtheshallowwaterequationsandthefinitevolumemethodonacurvilinearbody-fittedgrid.Themodeliscalibratedandvalidatedusingavailabletidaldataandfieldmeasurements.Thevelocityvectorfields,thetidallevels,thetrajectoriesofdroguesandthefarfieldsewagedilutionfromtheexistingandproposedoutfallsarestudiedforthespring/neaptideandthedry/wetseason.Theresultsshowthatthetidalcurrentsandtherunoffflowareabletodiluteanddispersethesewagefromtheoutfallstotheoutersea.ThesewagedilutioncontoursundervarioushydrodynamicconditionsindicatethatthedischargedeffluentatpresenthaverelativelyminorimpactonthewaterenvironmentoftheYangtzeEstuary;whereastheplannedsewageplanwouldsignificantlydeterioratethewaterqualityoftheestuaryintheabsenceofanytreatment,especiallyduringtheneaptideofdryseason.ThedroguetrackingshowsthattheeffluentfromthefourouffallswillbetransporteddownstreamtotheHangzhouBay.Astudyonthepollutionduetotheprojectandtheself-purificationcapacityofHangzhouBayisproposedinadditiontothatoftheYangtzeEstuary.
简介:Inordertoevaluatethevalidityofcommonlyusedformulaedescribingerosionanddepositionofcohesivesedimentsfortheirapplicationwithinnumericalsimulations,acombinedexperimentalandnumericalinvestigationiscarriedout.Anannularflumeisusedforexperimentsonerosionanddepositionofreservoirmuds.Theresultsoftheseexperimentsserveasvalidationdatafortheformulaeinconsideration.Forthisvalidation,theexperimentsarereproducedwithinanumericalsimulation,whichconsistsoftwoparts:Inafirststep,theflowintheannularflumeissimulatedwithina3Dlargeeddysimulation.Theflowfieldsobtainedinthesesimulationsthenserveasinputforthesecondstep,adecoupled2DVsimulationoferosionanddepositionprocessesduringtheexperiments.TheinvestigatedformulaearethoseofPartheniadesandParchure&MehtaconcerningerosionandofKroneandRichardson&Zakiconcerningdeposition.
简介:这份报纸在一条概念的冲积山谷为各种各样的情形论述模仿的隧道模式由一改善二维(2-D)数学模型在同伴纸描述了。从一样的起始的隧道开始,不同隧道模式为改变的边界和起始的条件在250天的一个实时时期上被模仿了包括入口水分泌物和沉积负担,河岸的起始的山谷斜坡,和erodibility。这些控制因素的影响被讨论,以在概念的河山谷的模仿的河的隧道,隧道十字节的几何学,和水表面侧面的纵的底部侧面。因为二部分的沉积运输条件极大地不同,结果建议一样的隧道的上面、更低的部分可以有不同平面形状。在控制变量和隧道模式之间的模仿的原因的关系与已知的隧道模式理论同意品质上。
简介:为河环境的保存和恢复,一种沉积补充技术,它传送在水坝下面从水库挖掘或挖出到河的沉积的部分被开发并且在几个水坝尝试性地被实现了。作为补充放的沉积能外面被冲洗并且由洪水或水坝版本下游地搬运了。冲洗沉积被期望贡献降级和低流动的隧道的变化的控制。然而,因为有许多未知因素,这种技术在发展阶段。因此,系统的调查为这种技术的实际管理是必要的。在这研究,沉积涌出上并且在降级的控制上的补充沉积的地点的效果借助于斜槽实验被调查。一个二维的数字模型也被开发进一步在河恢复上调查沉积扩大的效果。数字模型享受在固定的床上存侵蚀和沉积运输。模拟结果对试验性的结果被验证。补充沉积的涌出的过程首先被调查,然后它的效果作为为河床降级的一项反措施被分析。结果如下被总结:(1)扩大在上面翻动为补充沉积和低流动的隧道的变化涌出是有效的。(2)降级的改善能在放置的二种类型的情况中被发现。改善效果上面翻动放置比的大更低翻动在固定的床上的补充地点附近的床的沉积率是的放置(3)在大更低翻动放置与相比上面翻动放置。(4)数字模型被发现作为一个预兆的工具通常成功。
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简介:水坝裂缝流动的存在数字调查很少考虑植被的效果。这份报纸在活动、生长的床上为水坝裂缝流动论述一个平均深度的二维的模型。在模型,两个都,为由植被的存在存储质量和动量并且拖流动减少空间的后果被考虑:前者被把一个因素(1c)(1c)介绍给流动深度考虑,在c是植被密度的地方;以后被在动量方程包括一个另外的水池术语考虑。新管理方程是由有限体积方法的discretized;并且中央迎风的计划为水深度与静水力学的重建方法嵌入的存在秒顺序,被用来估计流动;来源术语被完成稳定性要求的明确或半明确的方法估计。与/没有植被效果/沉积运输的水坝裂缝流动或伪稳定的流动的实验室实验被模仿。在大小和数字模拟之间的好协议在复制流动深度,速度和床变丑深度表明模型的令人满意的表演。在一张活动、生长的床上的水坝裂缝流动的六种情形的数字案例研究被进行。植被分发的植被地区,植被密度,和模式的区域什么时候被改变,被看那,结果的床词法变化极大地不同,在水坝裂缝流动进化上建议植被的大影响。明确地,植被可以转移主要流动的方向,妨碍流动并且因此导致植被在上游的增加的免职。
简介:Adetaileddiscussionofexistingthreekindsofmathematicalmodelsofheavymetalpollutanttransport-transformationinfluvialriversispresented,withanemphasisonthemathematicalmodelofheavymetalpollutanttransport-transformationdynamics.Theimperfectionoftwokindsofmathematicalmodels,thatis,mathematicalmodelofchemicalthermodynamicequilibriumandthatofchemicalreactionkinetics,andtheshortcomingofexistingmathematicalmodelsofheavymetalpollutanttransport-transformationdynamicsarepointedout.Furthermore,thestructureofmathematicalmodelofheavymetalpollutanttransport-transformationdynamicsinfluvialriversissuggested.Equationsinthemathematicalmodelofheavymetalpollutanttransport-transformationdynamicsinfluvialriverswillbediscussedinthefollowingpaper.