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268 个结果
  • 简介:Fromthegroupmovementofthebedloadwithinthebottomlayer,detailsofthenonlineardynamiccharacteristicsofbedloadmovementarediscussedinthispaper.Whetherthesedimentisinitiatedintomotioncorrespondstowhethertheconstanttermintheequationisequaltozero.Ifconstanttermiszeroandnodispersiveforceisconsidered,theequationrepresentsthetraditionalShieldsinitiationcurve,andifconstanttermiszerowithoutthedispersiveforcebeingconsidered,thenanewShieldscurvewhichismuchlowerthanthetraditionaloneisgot.Thefixedpointoftheequationcorrespondstotheequilibriumsedimenttransportofbedload.Inthemutationanalysis,wehavefoundthattheinflectionpointisthedemarcationpointofbreaking.Intheory,thebreakingpointcorrespondstothedividingboundaryline,acrosswhichthebedformchangesfromflatbedtosandrippleorsanddune.ComparedwiththeexperimentaldataofChatouHydraulicLabinFrance,theconclusionsareverified.

  • 标签: 非线性机制 非线性动态特性 输沙 运动负荷 启动曲线 常数项
  • 简介:Effectofvelocityjumpandtemperaturejumpontheheatandmomentumtransferinmicro-domainsisdiscussedindetail.Asimulationaidedbylocallyfullydevelopedassumptionisdevelopedtoexplaintheexperimentalresultsdifferentfromthosepredictedbyconventionaltheory.Heattransferinmicro-channelsundertheuniformheatfluxisalsoanalyzed.Itisfoundthatvelocity-jumpandtemperature-jumphaveanoppositeinfluenceandNusseltnumberhasagreatervaluewhentheKnudsennumberisverysmall,WiththeincreasingofKnudsenNumber,Nussqltnumberbecamesmallerthan8.24.

  • 标签: 热传导 动量传输 微型通道
  • 简介:基于在在定义变量和常数利用的数据的可靠性和代表性之间的关系,众多的费时间的方程要求复杂参数估计水流带来的碎石运输。包括流动分泌物,水深度,水表面斜坡,和表面谷物直径在这学习容易可存取的数据(来自在马来西亚的小河的d50)被用来估计水流带来的碎石运输。基因编程(GP)和人工的神经网络(ANN)当模特儿当估计床的互补工具在小河里基于在简洁和精确性之间的平衡装载运输,被使用。发达模型为ANN和GP与97%和93%的全面精确性表明高效,分别地与另外的传统的方法和实验方程相比。

  • 标签: 马来西亚 河流泥沙 人工神经网络 推移质输沙 输送 中小河流
  • 简介:Laboratoryexperimentshavebeencarriedouttostudythecharacteristicsofsedimenttransportinsteepstreams.Thequestionisdiscussedwetheranarmouredsurfacesisdestroyedduetothetransportofmaterial,becauseadditionalimpulsesareactingonit,orthelayerisshelteredbythetransportedmaterial,becauseapartofthestreampowerisusedtomovethematerial.Accordingtotheresultsofthepresentedexperiments,inwhichtheinfluenceofthefeedingrateandthefeedingdurationhavebeeninvestigated,transportedmaterialreachinganarmouredriversectionfromupstreamalwaysremobilzesbedmaterial,whichisimmobileunderclearwaterflowconditions.Todecideifastaticarmourlayeriseitherdestroyedornot,twosimplecriteriawerechosen:oneconsideringthegrain-sizedistributionoftheerodedbedmaterial,andanother,whichreferestotheamountoferodedbedmaterial.

  • 标签: SEDIMENT transport BED stability Armored LAYER
  • 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.

  • 标签: 河流 输沙能力 总输沙量 改良BAGNOLD公式
  • 简介:NUMERICAL SIMULATION FOR CONTAMINANTS AND WATER TRANSPORT IN SOILSMERICALSIMULATIONFORCONTAMINANTSANDWATERTRANSPORTINSOILS¥Wa...

  • 标签: variably saturated flow GROUNDWATER numerical simulation
  • 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。

  • 标签: 泥沙输移 风生环流 北部湾 模拟 琼州海峡 河口沉积
  • 简介:Amodelforsimulatingcadmiumtransportinasoil-plantsystemwasbuiltusingacommercialsimulatingprogramnamedPowersimonthebasisofinput-outputprocesseshappeninginthesoil-plantsystem.COnvectiveanddispersivetransportprocessesofcadmiuminsoilprofileareembedded.Simulationsonadailybasehavebeendoneuptoatotalsimulatingtimeof250years,Resultsshowthatapplicationsofsewagesludgeandfertilizeratthesimulatedrateswouldonlycauseslightcadmiumaccumulationsineachlayerofthesoil,andcadmiumaccumulationwouldbelevellingoff,reachinganequilibriumconcentrationslayerbylayerdownwardaftercertaintime.Thetimescaletoreachanequilibriumconcentrationvariesfrom10yearsforthetopthreelayerstoover250yearsforthebottomlayers.Plantcadmiumuptakewouldincreasefrom52umm^-2underinitialsoilcadmiumconcentrationsto65ugm^-2underequilibriumsoilcadmiumconcentrations,whichwouldnotexceedthemaximumallowablecadmiumconcentrationinwheatgrains.Mainparameterswhichinfluencecadmiumaccumulationandtransportinsoilaretotalcadmiuminput,rainfall,evaporation,plantuptakeandsoilproperties.

  • 标签: 运移规律 土壤 庄稼 数值模拟 重金属污染
  • 简介:Thecalculationaccuracyofthesuspendedsedimenttransportratereliesonthatoftheverticaldistributionoftheparticleconcentration,theparticlevelocitydistributionandthereferenceconcentration.Inviewofthelimitationsoftheprevionsformulasforboththevelocityandtheconcentrationdistributions,generalexpressionsareintroducedtothecalculationofsus-pendedsedimenttransportrate.Basedontheseanalyses,asimpleandpracticalcalculationmodelisgiveninthepresentpaper.

  • 标签: suspended SEDIMENT TRANSPORT RATE CONCENTRATION PROFILE
  • 简介:Astudyonthetransportcharacteristicsofzincinlousoilwithphosphateatdifferentconcentrationswascarriedoutbythemethodofstepinput.Theeffectsofphosphateandtemperatureonzinctransportwerestudiedthroughanalysingthediffusion-dipsersioncoefficients(D)andtheretardationfactor(R)obtainedbytheprogramCXTFIT.TheresultsshowedthatDdecreasedandRincreasedwithincreasigconcentrationofphosphatesothativwasdifficultforzinctobreakthroughthesoilcolumn,andzincstoppedtobreakthroughthecolumnathightemperature.Oneorderequation,doubleconstantequationandtheElovichequationwereallsuitablefortheescriptionofzincdynamics.Effectsofphosphateandtemperatureonzinctransportwerefurtherconfirmedbytheanalysisonpseudo-thermodynamicparametersofzinctransport.

  • 标签: 扩散系数 磷酸盐 伪热力学参数 延迟因素 运移动力学
  • 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。

  • 标签: 混沌理论 数学 湍流 多相流
  • 简介:剧降钢笔nanolithography(DPN)是为直接与sub-50nm分辨率在表面上打印材料的一个有用方法。因为它从一个扫描探查尖端包含材料的物理运输到表面和和表面的那材料的随后的化学相互作用,当试图理解DPN时,有许多因素考虑。在这评论,我们概述为所知的物理、化学的过程在DPN起一个作用。通过文学的详细评论,我们基于他们的运输性质分类墨水进三个一般范畴,并且加亮DPN能被用来在一根扫描探针的尖端执行化学的无数方法。

  • 标签: 材料运输 纳米光刻 化学相互作用 扫描探针 传输性能 DPN
  • 简介:Theoperatortheoryonindefiniteinnerproductspacesisusedtodiscussthehalfrangeproblemoflineartransportequationwithindefinitecollisionoperator.Acounterexampleto[1]isgivenandarelationbetweenmeasuresofnonuniquenessandnoncompletenessisestablished.

  • 标签: COLLISION kerA DIAGONAL LEMMA assumed HOUGH
  • 简介:Thispaperdealswiththesolutionofaneutrontransportequationwithparameterδ.Usingthetheoryoffunctionalanalysis,wediscussthedistributionoftheparameterswhichmaketheequationhaveanon-zerosolution,andobtainanecessaryandsufficientconditionfortheexistenceofthecontrolcriticaleigenvalueδ0whichpossessesaphysicalmeaning.

  • 标签: Transport EQUATION δ-eigenvalue COMPACT OPERATOR POSITIVE
  • 简介:Thispaperdealswiththedeterminationoftheminimumnumberofgranulometricclassesthatshouldbeusedtocalculatesedimenttransportofnon-uniformgrain-sizematerials.Thisisveryimportanttoreducecomputationaleffortsinhydro-morphologicalmathematicalmodelsbasedonsedimentcontinuitybyfractions.Inthecaseoflog-normalriverbedgrain-sizedistributionstheincrementofthegeometricstandarddeviationitselfisalreadysufficienttodescribethecorrespondingaugmentofthenumberofclasses.However,stronglynon-uniformriverbedsediments(likethoseencounteredingravel-bedrivers)showcompletelydifferentstatisticalcharacteristicswhencomparedwiththeformerones.Hereinspecificrelationshipsaredevelopedwhichconfirmthatinthesecasesboththegeometricstandarddeviationandtheskewnessofthegrain-sizedistributionmustbetakenintoaccounttodefinetheminimumnumberofgrain-sizeclasses.

  • 标签: NON-UNIFORM sediments SEDIMENT TRANSPORT of mixtures
  • 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。

  • 标签: 输沙模式 通道 试验 实验手段 几何条件 渠道系统
  • 简介:Theshortcomingsofthepresenttwoformulaefordescribingcolumnholdupareanalyzedanddeductionsareadetofindanewformula,Thecolumnholdup,Hw,describedbythenewformulaisdimensional,andrelatedtosoilsoultetransportkinesisandcolumnphysicalproperties,Comparedwiththeothertwocolumnholdups,Hwisfeasibletodescribedimensionalcolumnholdupduringsolutetransportprocess,TherelationshipsbetweenHwandretardationfactor,R,indifferentsolutetransportboundaryconditionsareestablished.

  • 标签: 土壤 溶质 运移规律 柱滞留