简介：Adirectnumericalsimulationisperformedon2563gridsfordecayingisotropicturbulence.Thetotalkinematicenergy,Taylormicro-scale,Taylormicro-scaleReynoldsnumberandthevelocityderivativeskewnessarecalculated.Thesnapshotsofenergyspectraandenergytransferspectraareplotted.ThesemeasurementsverifytheDIApredictions:decayingisotropicturbulencehastheenergypropagationandoccupiesthefinaldecayperiods.Theskewnessremainstosomelevelwithsmallvariationeveninthefinaldecayperiod.

简介：Inthispaper,thewaves’breakingintheleewavesissuccessfullysimulatedbytheatmosphericmesoscalenumericalmodelwithasecond-ordertur-bulentclosure.Itisfurtherprovedthattheturbulenceinthewave-breakingregionplaystheroleofintensemixingfortheaveragefield,whichleadstothetrappingofupwardpropagatingwavesandthuspromotesthedevelopmentofthedownslopewind.Theturbulentstructureinthewave-breakingregionisdiscussedandthefol-lowingconclusionsareobtained:(1)Inthewave-breakingregion,theturbulentheatfluxestransferfrominsidetooutsideandtheturbulentmomentumfluxestransferfromoutsidetoinside.(2)Inthewave-breakingregion,theturbulentenergymainlycomesfromthewindshearandthebuoyancypromotestheturbulentdevelopmentonlyinpartoftheregion.(3)Intheupperpartofthewave-breakingregion,theturbulentmomentumfluxesbehaveasacounter-gradienttransfer.(4)Theturbulentmixinginthewave-breakingregionisnon-local.

简介：在这份报纸，我们在作者组进行的可压缩的骚乱上考察一些最近的研究，它在为围住墙的骚乱开发抑制大旋涡模拟(CLES)上在可压缩的各向同性的骚乱(市民)和应用研究上包括基本研究。在第一部分，我们实质上以最新建议的混合compactweighted开始为被用来构造市民的一个系统的数据库的市民模拟的nonoscillatory(WENO)计划。用这个数据库，可压缩的骚乱的各种各样的基本性质被检验了，包括统计并且从一个Lagrangian观点的可压缩的模式，shockletturbulence相互作用，小规模上的本地压缩的可能性的效果，动能串联，和一些初步的结果可伸缩。在第二部分，CLES的想法和公式被考察，处于可压缩的工程问题由CLES和一些应用程序的确认列在后面。

简介：

简介：

简介：Alaboratoryexperimentwasconductedinsideawindwavetanktoinvestigatethewaveinducedturbulence.Inthisexperiment,thewavesurfaceelevationandvelocitybeneaththewatersurfaceweremeasuredsimultaneouslytoinvestigatetherelationbetweenthewavestatusandwaveinducedturbulence.TheprofileoftheturbulentdissipationrateandReynoldsstresswerecalculatedusingexperimentaldata.Theeffectofthewavestatusonturbulenceisinvestigatedwithregardtothewindwave,swell,andmixedwaveconditions.Itwasdepictedthattheturbulencedecreasedwithincreasingdepthfromthewatersurfaceandthattheturbulencethatwasinducedbyawavewithlargerwavelengthandwaveheightismuchstrongerforthesamewavestatus.Finally,weobservedthatthewindwaveismoreeffectiveinactivatingthewaveinducedturbulence.

简介：Ｂｕｏｙａｎｔｆｌｏｗｉｓｏｎｅｏｆｔｈｅｆｕｎｄａｍｅｎｔａｌｆｌｏｗｓ．Ｔｈｅｄｉｆｆｅｒｅｎｃｅｏｆｄｅｎｓｉｔｙｂｅｔｗｅｅｎｄｉｓｃｈａｒｇｅｄｆｌｕｉｄａｎｄｔｈｅａｍｂｉｅｎｔｆｌｕｉｄｃａｎｃａｕｓｅｂｕｏｙａｎｔｔｕｒｂｕｌｅｎｔｆ...

简介：ThispaperprovidesacomprehensiveintroductiontothemajorprogressintransitionandturbulencestudiesinChinaoverthepastthirtyyears.Despitetheauthor’sbestefforts,therearesomeunavoidableomissions.Weexpectthatwiththecontinueddeepeningofturbulenceresearch,Chinesescholarswillmakeincreasingcontributionsinthisfield,whichwillcertainlyhavestronginfluenceontheestablishmentofaChinaSchoolofTurbulence.

简介：Mostfluidflowsinnatureandengineeringapplicationsareinthestateofturbulence.Turbulentmotionsusuallyexhibitawiderangeofspatialandtemporalscales,suchastheflowofnaturalgasandoilinpipelines,thewakesofcarsandsubmarines,theboundarylayerofanaircraft,thecurrentintheoceansurface,theatmosphericboundarylayer,theinterstellargasclouds(gaseousstars),andtheEarth’swakeinthesolarwind.Turbulencecangreatlyimprovetheheatandmasstransferefficiencyofmacroscopicflow.Forexample,chemicalengineersuseturbulencetomixupandhomogenizefluidcomponentsandtoincreasechemicalreactionratesinliquidsorgases.However,turbulencecanalsoleadtoincreasesindrag,aerodynamicheat,andhydrodynamicandaerodynamicnoise.Forinstance,theaerodynamicloadingofhigh-speedaircraftcanbesignificantlyincreasedduetoturbulence.

简介：Thenumericalandphysicalissuesofsimulationsoncompressibleturbulencearereviewedinthepresentpaper.Anoutlineoftheglobalspectralmeth-odsandtheprogressofrecentlocalspectralmethodsareillustrated.Severaltypicalsubjectsinthisfieldarestudied,includinghomogeneousisotropicturbulence,au-toignitioninpremixedturbulence,interactionbetweenflamesandturbulence,andshockwaveinturbulence.Theresultsofthenumericalsimulationsarediscussed,enablingustodiscoverandtounderstandthephysicalphenomenawhichhavenotbeensolvedbyexperiments.

简介：Wefindanasymptoticexpressionforthecharacteristictimescalesofdecorrelationprocessesinweaklycompressibleandisothermalturbulence.ThisresultisusedintheEddy-DampedQuasi-NormalMarkovianequationtoderivethescalingsofcompressibleenergyspectra:(1)iftheacousticwavesaredominant,thecompressibleenergyspectraexhibit?7/3scaling;(2)iflocaleddystrainingisdominant,thecompressibleenergyspectraarescaledas?3.Meanwhile,theenergyspectraofincompressiblecomponentsdisplaythesamescalingof?5/3asthoseinincompressibleturbulence.Thedirectnumericalsimulationsofweaklycompressibleturbulenceareusedtoexaminethescaling.

简介：TheHongKongObservatory(HKO)provideslow-levelturbulencealertingservicefortheHongKongInternationalAirport(HKIA)throughthewindshearandturbulencewarningsystem(WTWS).IntheWTWS,turbulenceintensitiesalongtheflightpathsoftheairportareestimatedbaseduponcorrelationequationsestablishedbetweenthesurfaceanemometerdataandtheturbulencedatafromresearchaircraftbeforetheopeningoftheairport.Theresearchaircraftdataarenotavailableonday-to-daybasis.Theremotesensingmeteorologicalinstruments,suchastheDopplerlightdetectionandranging(LIDAR)andradar,maybeusedtoprovidedirectmeasurementsofturbulenceintensitiesovertherunwaycorridors.TheperformancesofLIDAR-andradar-basedturbulenceintensitydataarestudiedinthispaperbasedonactualturbulenceintensitymeasurementsmadeon423commercialjetsforatypicalcaseofterrain-inducedturbulenceinassociationwithatyphoon.Itturnsoutthat,withthetuningoftherelativeoperatingcharacteristic(ROC)curvebetweenhitrateandfalsealarmrate,theLIDAR-basedturbulenceintensitymeasurementperformsbetterthantheanemometer-basedestimationofWTWSforturbulenceintensityatmoderatelevelorabove.Ontheotherhand,theradar-basedmeasurementdoesnotperformaswellwhencomparedwithWTWS.BycombiningLIDAR-andradar-basedmeasurements,theperformanceisslightlybetterthanWTWS,mainlyasaresultofcontributionfromLIDAR-basedmeasurement.Asaresult,theLIDAR-basedturbulenceintensitymeasurementcouldbeusedtoreplaceanemometer-basedestimatefornon-rainyweatherconditions.Furtherenhancementsofradar-basedturbulenceintensitymeasurementinrainwouldbenecessary.

简介：到流入的骚乱发展的敏感狂暴的统计在microscale被调查城市的大气的环境流动。大旋涡的模拟(更少)被执行，在哪个流入误差被根据雷纳兹应力或精力系列转变一块充分发达的狂暴的地引进。理论分析被在狂暴的动能的预算方程忽视散开术语执行。结果显示出那，错误由雷纳兹压力腐烂引起了直到充分发达的水平的(i)被完成，并且(ii)典型长度规模引起的错误立即增加然后减少。当垂直坐标增加时，改变流入错误的率的streamwise变弱。内部层的流入和外部层的数据的效果的进一步的测试显示出那，流入内部层的数据统治近的域，和流入外部层的数据统治远域。

简介：Hydrodynamicinstabilityandthemechanismsforturbulenceonsetandself-sustainingaretworesearchquestionsthathavepuzzledthescientistsforoveracentury,yetrenewedinterestandsignificantprogressoccurredinthelastdecadeorso.WeknowonlyfewexactanalyticalsolutionsoftheNavier-Stokesequations,theequationsgoverningtheflowofsimplefluidslikewaterandair,andmostoftheseareneverobservedinapplicationsorlaboratory

简介：Experimentalandnumericalstudieshaveshownsimilaritiesbetweenlocalizedturbulenceinchannelandpipeflows.Byscalinganalysisofadisturbed-flowmodel,thispaperproposesalocalReynoldsnumberReMtocharacterizethethresholdoftransitiontriggeredbyfinite-amplitudedisturbances.TheReMrepresentsthemaximumcontributionofthebasicflowtothemomentumratiobetweenthenonlinearconvectionandtheviscousdiffusion.ThelowercriticalReMobservedinexperimentsofplanePoiseuilleflow...

简介：Inthispaper,westudytherelationbetweentheenergyspectrumexponentofturbulenceandfractaldimension,andgivetwoempiricalformulas.

简介：Theoreticalresultsonthescalingpropertiesofturbulentvelocityfieldsarereportedinthisletter.BasedontheKolmogorovequationandtypicalmodelsofthesecond-orderstatisticalmoments(energyspectrumandthesecond-orderstructurefunction),wehavestudiedtherelativescalingusingtheESSmethod.ItisfoundthattherelativeEESscalingexponentS_2isgreaterthantherealortheoreticalinertialrangescalingexponentξ_2,whichisattributedtoanevidentbumpintheESSrange.

简介：ByanalyzingturbulencedatameasuredattwositesincoastalregionsofHangzhoubay,itisdiscoveredthat:(1)TheturbulentintensityI_kisinverselyproportionaltothewindspeedatlowerspeed.Whileathigherwindspeed,itkeepsbasicallytobeconstant.(2)Undertheunstableconditionsinthevicinityofseashore,thedimensionlessstandarddeviationsofwindspeedσ_k/U(?)areconstantsbasically,whileintheinland,theycanbedescribedbytheexpressionssimilartoPanofsky(1977)modelsbutwithdifferentconstants.Underthestableconditions,theyareconstantswhenZ/L<0.2andproportionalto1/3powerofZ/LforlargerZ/L.(3)Nearthecoast,thevariationofU(?)/UwithZ/LfollowsBusinger(1971)modelU(?)/U=k/(?)(Z/L)verywellnotonlyunderstablebutalsounderunstablecondition.Inland,itiscoincidentverywellmerelyunderthecondition-1.0≤Z/L≤0.3.Outthisrange,thedeviationislarge.(4)ThedispersionparameterscanbedescribedintheformrecommendedbyDraxler(1976)butwithdifferentconstants.Undertheunstablecondition,theycanalsobeexpressedasBriggs(1985)modelwithdifferentconstants.

简介：Arecentlyintroducednonlinearmodelundergoesevaluationsbasedontwoisotropicturbulentcases:aUniversityofWiscosion-MadisoncaseatamoderateReynoldsnumberandaJohnsHopkinsUniversitycaseatahighReynoldsnumber.Themodelusesanestimationofthesubgrid-scale(SGS)kineticenergytomodelthemagnitudeoftheSGSstresstensor,andusesthenormalizedvelocitygradienttensortomodelthestructureoftheSGSstresstensor.Testingisperformedforthefirstcasethroughacomparisonbetwee...

简介：实验与1.5m和四个不同斜坡的经常的长度在一个2-dimentional水池上被执行。速度，雷纳兹压力和骚乱紧张的分布在这份报纸被学习了。结果证明当流动在出口斜坡上面继续，流动速度在隧道床附近增加，减少接近水表面。流动分离没被副词在床形式的冠观察。另外，分离地区的长度与增加入口和出口斜坡增加。最大值使正常化的最大的斜坡角度原因砍应力。基于实验，雷纳兹的形状强调分发通常依赖于入口和水池的出口斜坡，这被结束。另外，雷纳兹压力分发的形状被速度并且加速流动影响。随斜坡角度的增加，另外，第二等的水流被开发并且变得更稳定。在流动和床形式之间的动量主要被转由的象限分析表演的结果扫并且喷射事件。