简介：Inthispaper,amodifiedκ-εturbulencemodel,asimplifiedalgebraicstressmodelandadevelopedtwo-fluidmodelhavebeenpresentedbasedonnumericalmodelingofturbulentbuoyantrecirculatingflows.Thecalculatedresultsbythesemodelsareingoodagreementwithexperiments.However,thelastmodelismuchbetterforsimulatinggravity-stratifiedflows.

简介：周期性地强迫的空间地扩大的Brusselator在混乱政体被调查。我们探索在各种各样的强迫的频率和强迫的振幅下面产生的反响或非反响的模式。反响的空间地一致的摆动和不规则的结构被发现。而且，常规空间模式的二种类型在适当参数下面被产生。我们数字模拟的结果证明周期的力量能给上升在类似于常规摆动的强迫的系统的状况的空间与时间的混乱的强迫的系统撕了浊音模式。

简介：Mostcurrentcomputationsoftrubulentflowswithsecond-momentclosureadoptthediffusionmo-delswhichneglecttheeffectofpressure-velocitycorrelation.lnthepresentpapertheimportanceofthiscorrelationeffectiselucidatedtheneglectofthiseffectaccountsforsomemajordefectsinthewideapplicationofthese-cond-momentclosures.Throughtherelationbetweenand,establishedbyLumley,weproposehereanewturbulencediffusionmodelwhichtakesintoconsiderationthepressureeffect.Applicationsofthisnewmodelinthecomputationofshearlessturbulencemixinglayerandplane-andround-jetflowsshowthatthespreadingrateoftheseflowscanbesatisfactorilycaptured.

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简介：TheFourthInternationalSymposiumonRefinedFlowModellingandTurbulenceMeasurementsorganizedbyInternationalAssociationforHydraulicResearch(IAHR),andco-sponsoredbyagroupofChineseInstitutesheadedbyWuhanUniversityofHydraulic&EiectricEngineeringandChineseInstituteofWaterConservancyandHydroelectricPowerResearchistobeheldonSeptember20-23,1990atWuhanCity,People’sRepublicofChina.TheSymposiumisintendedforpresentationdiscussionandexchangeofviewsbetweeninternationalcolleaguesonawidescopeoffrontierproblemsregardingrefinedflowmodellingandturbulencemeasurements.Themaintopicsare:

简介：Inthispaper,wepresentanextensivestudyofthelinearlyforcedisotropicturbulence.Byusinganalyticalmethod,weidentifytwoparametricchoices,ofwhichtheyseemtobenewasfarasourknowledgegoes.WeprovethattheunderlyingnonlineardynamicalsystemforlinearlyforcedisotropicturbulenceisthegeneralcaseofacubicLienardequationwithlineardamping.WealsodiscussaFokker–Planckapproachtothisnewdynamicalsystem,whichisbistableandexhibitstwoasymmetricandasymptoticallystablestationaryprobabilitydensities.

简介：Ingasturbineengines,laminar-turbulenttransitionoccurs.However,generally,theturbulencemodelstodescribesuchtransitionresultsintooearlyandtooshorttransition.Combiningaturbulencemodelwithadescriptionofintermittency,i.e.thefractionoftimetheflowisturbulentduringthetransitionphase,canimproveit.Bylettinggrowtheintermittencyfromzerotounity,startandevolutionoftransitioncanbeimposed.Inthispaper,amethodwhereadynamicequationofintermittencycombiningwithatwo-equationk-ωturbulencemodelisdescribed.Thisintermittencyfactorisapremultiplicatoroftheturbulentviscositycomputedbytheturbulencemodel.FollowingasuggestionbyMenteretal.[1],thestartoftransitioniscomputedbasedonlocalvariables.

简介：Inunderwateropticalwirelesscommunication(UOWC),achannelischaracterizedbyabundantscattering/absorptioneffectsandopticalturbulence.MostpreviousstudiesonUOWChavebeenlimitedtoscattering/absorptioneffects.However,experimentsintheliteratureindicatethatunderwateropticalturbulence(UOT)cancauseseveredegradationofUOWCperformance.Inthispaper,wecharacterizeanUOWCchannelwithbothscattering/absorptionandUOTtakenintoconsideration,andaspatialdiversityreceiverscheme,sayasingleinput–multiple-output(SIMO)scheme,basedonalight-emitting-diode(LED)sourceandmultipledetectorsisproposedtomitigatedeepfading.TheMonteCarlobasedstatisticalsimulationmethodisintroducedtoevaluatethebit-error-rateperformanceofthesystem.Itisshownthatspatialdiversitycaneffectivelyreducechannelfadingandremarkablyextendcommunicationrange.

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简介：在这份报纸，在骚乱边界层与的流动的数字研究不利并且压力坡度(APG)被使用平均Reynolds的海军司烧(RANS)进行方程。这研究选六为典型骚乱模型，它对计算精确，并且到评估APG的问题批评。本地摩擦抵抗系数在数字、试验性的结果之间被比较。无尺寸的平均速度侧面的一样的比较也被执行。威尔科克斯(2006)k-w产生的结果离试验性的数据很靠近，这被发现。同时，象狂暴的动能和Reynolds压力那样的狂暴的数量也被学习。

简介：Theinfluenceofairturbulenceonthetransversewanderingofasinglefemtosecondlaserfilamentisstudiedbynumericalsimulation.Theresultsshowthattheaveragetransversedisplacementofthesinglefilament(δr}isproportionaltothesquarerootofturbulentstructureconstantandtherelationsbetweenandthepropagationdistancecanbefitbyapowerfunction.Inaddition,byusinganaxiconasafocusingoptics,thewanderingofasinglefilamentissuggestedtobestrongerthanthefree-propagationcase.

简介：Experimentswereconductedinawatertunnelbytomographictime-resolvedparticleimagevelocimetry(Tomo-TRPIV).TheReynoldsnumberReθis2460onthebaseofmomentumthickness.Accordingtothephysicalmechanismofthestretchandcompressionofmulti-scalevortexstructuresinthewall-boundedturbulence,thetopologicalcharacteristicsofturbulencestatisticsinlogarithmiclayerwereillustratedbylocal-averagedvelocitystructurefunction.Duringcoherentstructuresbursting,resultsrevealthatthetopologicalstructuresofvelocitygradients,velocitystrainratesandvorticitiesbehaveasantisymmetricquadrupolemodes.Athree-layerantisymmetricquadrupolevortexpacketconfrmsthatthereisatightrelationshipbetweentheouterlayerandthenear-walllayer.

简介：Smallconcentrationsofahigh-molecular-weightpolymerhavebeenusedtocreateso-called'elasticturbulence'inamicro-scaleserpentinechannelgeometry.Itisknownthattheinteractionoflargeelasticstressescreatedbytheshearingmotionwithinthefluidflowwithstreamlinecurvatureoftheserpentinegeometryleadsinitiallytoapurely-elasticinstabilityandthenthegenerationofelasticturbulence.Weshowthatthiselasticturbulenceenhancestheheattransferatthemicro-scaleinthisgeometrybyupto300%undercreepingflowconditionsincomparisontothatachievedbytheequivalentNewtonianfluidflow.

简介：TheUSM-θmodelofpowerlawfluidfordensetwo-phaseturbulentflowwasdeveloped,whichcombinestheunifiedsecond-ordermomentmodelfortwo-phaseturbulencewiththeparticlekinetictheoryfortheinter-particlecollision.Thismodelwasusedtosimulatetheturbulentflowofpowerlawfluidsingle-phaseinpipe.ItisshownthattheUSM?θmodelhasbetterpredictionresultthanthekf?εf?kp?εp?θmodel.TheUSM?θmodelwasthenusedtosimulatethedensetwo-phaseturbulentupflowofpowerlawfluidwithparticles.Withtheincreaseoftheflowexponent,thevelocitiesofpowerlawfluidandparticlesincreasenearthepipecentre.Comparisonbetweenthetwo-phaseflowofpowerlawfluid-particleandofliquid-particleindicatesthattheaxialfluctuationvelocityoffluidphaseandparticlephaseinliquid-particletwo-phaseflowissmallerthanthatinthepowerlawfluidtwo-phaseflow,butthetwo-phasevelocitiesofpowerlawfluid-particleandliquid-particleareclosetoeachother.

简介：大旋涡模拟(LES)被用来调查形成对照的动态特征砍骚乱(圣)和在表面的兰米尔循环(LC)混合了层(SML)。圣被在SML强迫的风通常导致。LC能被包括强迫的风，波浪和旋涡的角色的波浪水流相互作用驾驶。LES结果证明LC压制水平速度并且极大地修改顺风的速度侧面，但是增加垂直速度。LC的强壮的downwelling喷气加速并且增加向下作为与圣塞相比精力搬运垂直旋涡粘性KL的m比混合的圣斯特朗的由LC导致的大得多有二个地点。他们位于2s3s(司烧深度规模)并且SML的更低的层分别地。它的价值和位置随着时间周期性地变化。相反，最大的K圣导致的m位于SML的中间的深度。LC产生的狂暴的动能(TKE)由在TKE和Km是明显的。因此，LC的parameterization不能完全基于TKE。为深SML，在LC的大规模旋涡的传送对流起一个主要作用在向下，精力和LC的运输能导致更强壮的速度砍(SML底附近的S2)。另外，LC导致的大规模旋涡和S2总是正在变化，它需要充分在LC的parameterization被考虑。

简介：ＡＴＭＯＳＰＨＥＲＩＣＴＵＲＢＵＬＥＮＣＥＩＮＴＥＮＳＩＴＹＡＮＤＤＩＦＦＵＳＩＯＮＰＡＲＡＭＥＴＥＲＯＶＥＲＣＯＭＰＬＩＣＡＴＥＤＴＯＰＯＧＲＡＰＨＹＯＦＥＡＳＴＥＲＮＧＵＡＮＧＤＯＮＧＷｕＹａｎｂｉａｏ（吴艳标）；ＬｉｕＳｈｕｗａｎｇ（刘树旺）ａ...

简介：Theabsenceofsub-gridscale(SGS)motionsleadstosevereerrorsinparticlepairdynamics,whichrepresentsagreatchallengetothelargeeddysimulationofparticle-ladenturbulentflow.Inordertoaddressthisissue,datafromdirectnumericalsimulation(DNS)ofhomogenousisotropicturbulencecoupledwithLagrangianparticletrackingareusedasabenchmarktoevaluatethecorrespondingresultsoffilteredDNS(FDNS).ItisfoundthatthefilteringprocessinFDNSwillleadtoanonmonotonicvariationoftheparticlecollisionstatistics,includingradialdistributionfunction,radialrelativevelocity,andthecollisionkernel.Thepeakofradialdistributionfunctionshiftstothelarge-inertiaregionduetothelackofSGSmotions,andtheanalysisofthelocalflowstructurecharacteristicvariableatparticlepositionindicatesthatthemosteffectiveinteractionscalebetweenparticlesandfluideddiesisincreasedinFDNS.Moreover,thisscaleshiftinghasanobviouseffectontheodd-ordermomentsoftheprobabilitydensityfunctionofradialrelativevelocity,i.e.theskewness,whichexhibitsastrongcorrelationtothevarianceofradialdistributionfunctioninFDNS.Asawhole,theradialdistributionfunction,togetherwithradialrelativevelocity,cancompensatetheSGSeffectsforthecollisionkernelinFDNSwhentheStokesnumberbasedontheKolmogorovtimescaleisgreaterthan3.0.However,itstillleavesconsiderableerrorsforStk<3.0.

简介：纠缠的轨道的尖动量(操作维护管理)在Kolmogorov弱骚乱宣传的三个光子被调查。这里，单个阶段屏幕模型被用来学习操作维护管理光子的纠纷进化。结果显示有更高的操作维护管理模式的纠缠的操作维护管理three-qubit状态将对骚乱是更柔韧的。而且，纠缠的操作维护管理three-qubit状态为小操作维护管理价值有更高全面的传播，这被发现。

简介：基于测量系统的3DPTV(追踪Velocimetry的粒子)，有四条不同直径的粒子的3D运动特征被调查。在特定的流动条件下面，粒子的3D运动上的粒子直径的影响被学习，并且骚乱特征被不同统计方法分析。当直径增加了，结果证明粗糙的粒子的骚乱紧张减少了。在近的墙区域，纵、垂直的变化速度的概率密度分布两个都从正常分发背离了；当时在外部区域，垂直变化速度的概率密度分发近似同意了正常分发。