简介:Fromthegroupmovementofthebedloadwithinthebottomlayer,detailsofthenonlineardynamiccharacteristicsofbedloadmovementarediscussedinthispaper.Whetherthesedimentisinitiatedintomotioncorrespondstowhethertheconstanttermintheequationisequaltozero.Ifconstanttermiszeroandnodispersiveforceisconsidered,theequationrepresentsthetraditionalShieldsinitiationcurve,andifconstanttermiszerowithoutthedispersiveforcebeingconsidered,thenanewShieldscurvewhichismuchlowerthanthetraditionaloneisgot.Thefixedpointoftheequationcorrespondstotheequilibriumsedimenttransportofbedload.Inthemutationanalysis,wehavefoundthattheinflectionpointisthedemarcationpointofbreaking.Intheory,thebreakingpointcorrespondstothedividingboundaryline,acrosswhichthebedformchangesfromflatbedtosandrippleorsanddune.ComparedwiththeexperimentaldataofChatouHydraulicLabinFrance,theconclusionsareverified.
简介:Effectofvelocityjumpandtemperaturejumpontheheatandmomentumtransferinmicro-domainsisdiscussedindetail.Asimulationaidedbylocallyfullydevelopedassumptionisdevelopedtoexplaintheexperimentalresultsdifferentfromthosepredictedbyconventionaltheory.Heattransferinmicro-channelsundertheuniformheatfluxisalsoanalyzed.Itisfoundthatvelocity-jumpandtemperature-jumphaveanoppositeinfluenceandNusseltnumberhasagreatervaluewhentheKnudsennumberisverysmall,WiththeincreasingofKnudsenNumber,Nussqltnumberbecamesmallerthan8.24.
简介:Laboratoryexperimentshavebeencarriedouttostudythecharacteristicsofsedimenttransportinsteepstreams.Thequestionisdiscussedwetheranarmouredsurfacesisdestroyedduetothetransportofmaterial,becauseadditionalimpulsesareactingonit,orthelayerisshelteredbythetransportedmaterial,becauseapartofthestreampowerisusedtomovethematerial.Accordingtotheresultsofthepresentedexperiments,inwhichtheinfluenceofthefeedingrateandthefeedingdurationhavebeeninvestigated,transportedmaterialreachinganarmouredriversectionfromupstreamalwaysremobilzesbedmaterial,whichisimmobileunderclearwaterflowconditions.Todecideifastaticarmourlayeriseitherdestroyedornot,twosimplecriteriawerechosen:oneconsideringthegrain-sizedistributionoftheerodedbedmaterial,andanother,whichreferestotheamountoferodedbedmaterial.
简介:Thispaperre-examinesBagnold’stheoremofsedimenttransport.DifferentfromthestreampowerdefinedbyBagnold,i.e.,τoV,thisstudyshowsthatthetotalloadofsediment-ladenflow,gt,isrelatedtonearbedenergydissipationrate,i.e.,τou*’.Anattemptismadetoexplaintheempiricalrelation.Theratio(=k)ofmeasuredtotalload,gt,totheproductofnearbedvelocity,u*’,andenergydissipationrate,τou*’,isanalyzed.ItisfoundthatkisindependentoftheRousenumber,Z,ifZisgreaterthan2.6,butthecoefficientkdecreaseswiththeincreaseofZwhenZ<2.6.AnempiricalrelationbetweenkandZisdeveloped.Asystematicandthoroughanalysisof1,458setsofdatacollectedfrom16riversandcanalsconfirmsthattheproposedformulacanbeusedtocomputethetotalloadwithaccuracy.
简介:NUMERICAL SIMULATION FOR CONTAMINANTS AND WATER TRANSPORT IN SOILSMERICALSIMULATIONFORCONTAMINANTSANDWATERTRANSPORTINSOILS¥Wa...
简介:在Beibu海湾的水循环和沉积运输为它的环境保护和资源利用是重要的。由采用为系统(ROMS)建模的地区性的海洋,我们在Beibu海湾学习了循环,沉积运输和长期的词法进化的季节的变化。模拟结果证明潮和风导致的发行量在海湾在冬季和夏天两个都是气旋的并且风驱动的发行量在夏天比那在冬季是更强壮的。沉积集中在Qiongzhou海峡,海南岛的西方和越南和Leizhou半岛的海岸是更高的。沉积在Qiongzhou海峡在夏天在冬季并且向东向西被搬运。Qiongzhou海峡的西方入口被统治由向西一整年搬运。在河边解除的沉积在河嘴附近被扔。模仿的结果证明沉积运输被潮汐的导致的底部暂停主要在Beibu海湾控制。四个特征为侵蚀和免职的分发模式被总结。(1)侵蚀和免职最是不足道的在里面海湾的区域。(2)沉积免职在Qiongzhou海峡的嘴是更重要的。(3)侵蚀在Qiongzhou海峡的海床被观察。(4)侵蚀和免职在海南岛的西方或者发生。
简介:Amodelforsimulatingcadmiumtransportinasoil-plantsystemwasbuiltusingacommercialsimulatingprogramnamedPowersimonthebasisofinput-outputprocesseshappeninginthesoil-plantsystem.COnvectiveanddispersivetransportprocessesofcadmiuminsoilprofileareembedded.Simulationsonadailybasehavebeendoneuptoatotalsimulatingtimeof250years,Resultsshowthatapplicationsofsewagesludgeandfertilizeratthesimulatedrateswouldonlycauseslightcadmiumaccumulationsineachlayerofthesoil,andcadmiumaccumulationwouldbelevellingoff,reachinganequilibriumconcentrationslayerbylayerdownwardaftercertaintime.Thetimescaletoreachanequilibriumconcentrationvariesfrom10yearsforthetopthreelayerstoover250yearsforthebottomlayers.Plantcadmiumuptakewouldincreasefrom52umm^-2underinitialsoilcadmiumconcentrationsto65ugm^-2underequilibriumsoilcadmiumconcentrations,whichwouldnotexceedthemaximumallowablecadmiumconcentrationinwheatgrains.Mainparameterswhichinfluencecadmiumaccumulationandtransportinsoilaretotalcadmiuminput,rainfall,evaporation,plantuptakeandsoilproperties.
简介:Thecalculationaccuracyofthesuspendedsedimenttransportratereliesonthatoftheverticaldistributionoftheparticleconcentration,theparticlevelocitydistributionandthereferenceconcentration.Inviewofthelimitationsoftheprevionsformulasforboththevelocityandtheconcentrationdistributions,generalexpressionsareintroducedtothecalculationofsus-pendedsedimenttransportrate.Basedontheseanalyses,asimpleandpracticalcalculationmodelisgiveninthepresentpaper.
简介:Astudyonthetransportcharacteristicsofzincinlousoilwithphosphateatdifferentconcentrationswascarriedoutbythemethodofstepinput.Theeffectsofphosphateandtemperatureonzinctransportwerestudiedthroughanalysingthediffusion-dipsersioncoefficients(D)andtheretardationfactor(R)obtainedbytheprogramCXTFIT.TheresultsshowedthatDdecreasedandRincreasedwithincreasigconcentrationofphosphatesothativwasdifficultforzinctobreakthroughthesoilcolumn,andzincstoppedtobreakthroughthecolumnathightemperature.Oneorderequation,doubleconstantequationandtheElovichequationwereallsuitablefortheescriptionofzincdynamics.Effectsofphosphateandtemperatureonzinctransportwerefurtherconfirmedbytheanalysisonpseudo-thermodynamicparametersofzinctransport.
简介:不同液体的混乱混合生产旋绕的结构到分开这些液体的接口。为能溶合的液体(是这里考虑了),这个接口被定义为50%集体集中isosurface。为导致的冲击波(Richtmyer-Meshkov)不稳定性,我们发现接口当计算网孔被精制,逐渐地复杂。如果Kolmogorov规模相对网孔是小的,这界面的混乱被粘性,或由计算网孔割掉。在集成的接口统计的政体,我们然后检验混合,即集中统计,由质量调整了散开。为比统一显著地大的Schmidt数字,典型地代表液体或稠密的血浆,另外的网孔精炼通常被需要克服数字集体散开并且完成混合问题的一个集成的答案。然而,与前面追踪的利益并且与一个算法,那允许有限接口散开,我们能在Schmidt数字一致地保证集中。我们证明不同答案源于Schmidt数字的变化。我们建议潜水艇格子粘性和可能在现实主义的格子层次允许集成的答案的集体散开parameterizations。
简介:Thispaperdealswiththesolutionofaneutrontransportequationwithparameterδ.Usingthetheoryoffunctionalanalysis,wediscussthedistributionoftheparameterswhichmaketheequationhaveanon-zerosolution,andobtainanecessaryandsufficientconditionfortheexistenceofthecontrolcriticaleigenvalueδ0whichpossessesaphysicalmeaning.
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简介:Thispaperdealswiththedeterminationoftheminimumnumberofgranulometricclassesthatshouldbeusedtocalculatesedimenttransportofnon-uniformgrain-sizematerials.Thisisveryimportanttoreducecomputationaleffortsinhydro-morphologicalmathematicalmodelsbasedonsedimentcontinuitybyfractions.Inthecaseoflog-normalriverbedgrain-sizedistributionstheincrementofthegeometricstandarddeviationitselfisalreadysufficienttodescribethecorrespondingaugmentofthenumberofclasses.However,stronglynon-uniformriverbedsediments(likethoseencounteredingravel-bedrivers)showcompletelydifferentstatisticalcharacteristicswhencomparedwiththeformerones.Hereinspecificrelationshipsaredevelopedwhichconfirmthatinthesecasesboththegeometricstandarddeviationandtheskewnessofthegrain-sizedistributionmustbetakenintoaccounttodefinetheminimumnumberofgrain-sizeclasses.
简介:融合是加入流动的集中创造复杂流动和生产强壮的流动发行量并且在床形态学的快速的变化的沉积运输模式的自然、人造的隧道系统的普通特征。由几活动床的隧道融合的实验室实验的工具,这研究(1)调查并且提出(不听说得好)在隧道融合导致沉积的早期的运动的流动和几何条件,并且(2)在主要词法特征上描绘流动和几何条件的效果(例如搜索和免职区域)在融合。在这研究被考虑的主要重要性因素中是流动弗鲁德数字,融合的角度,分泌物和宽度比率和床军事性质。这试验性的研究为更好理解在隧道融合涉及沉积运输和床形态学的机制提供卓见并且也确定沉积上的各种各样的流动和几何因素的影响搬运图案和河的研究,它是在河工程的大重要性。
简介:Theshortcomingsofthepresenttwoformulaefordescribingcolumnholdupareanalyzedanddeductionsareadetofindanewformula,Thecolumnholdup,Hw,describedbythenewformulaisdimensional,andrelatedtosoilsoultetransportkinesisandcolumnphysicalproperties,Comparedwiththeothertwocolumnholdups,Hwisfeasibletodescribedimensionalcolumnholdupduringsolutetransportprocess,TherelationshipsbetweenHwandretardationfactor,R,indifferentsolutetransportboundaryconditionsareestablished.