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149 个结果
  • 简介:Withthedevelopmentofhigh-resolutionandmulti-scaleunifiednumericalmodel,someoftechniquesaboutnon-hydrostaticmeso-scalenumericalweatherpredictionareaddressed.Theimpactoftheverticalcoordinatesystemisoneofthem.Inthispaper,basedonaWRF(WeatherResearchandForecast)model,theimpactonthecalculationofverticalvelocitywasstudiedwithdifferentverticalcoordinates.Thesimulationresultsshowedthatthecalculationofverticalvelocityissensitivetoverticalcoordinates.Itisespeciallymoreevidentwhentheresolutionincreased.Duetothecloserelationshipsbetweenverticalvelocityandprecipitation,thedifferenceofverticalvelocityinevitablyinfluencesmodel'sdescriptionofprecipitation.Anidealexperimentexhibitsthatpressuregradientforcecomputationsinthepressureterrain-followingcoordinatearesensitivetosurfacepressure.

  • 标签: 数值预报模型 协调系统 运动速度 垂直方向 天气预报
  • 简介:Densitystratifiedflowwithboththeverticaltemperaturegradientandtheverti-calsalinitygradientissimulatednumerically,inwhichturbulenttermsarecalculatedbyasim-plifiedturbulencestress/fluxalgebraicmodel.Thefeatureofstratificationandturbulenceisde-scribedcorrectlybythemodel.Thecomputationalresultsagreewellwiththeexperimentaldata.However,thek-eturbulencemodelisnotsosuccessful.

  • 标签: STRATIFIED flow TURBULENCE model environment NUMERICAL
  • 简介:Thepresentworkprovidesanovelmethodforcalculatingverticalvelocitybasedoncontinuityequationsinapressurecoordinatesystem.Themethodovercomesthedisadvantageofaccumulationofcalculatingerrorsofhorizontaldivergenceincurrentkinematicsmethodsduringtheintegrationforcalculatingverticalvelocity,andconsequentlyavoidsitssubsequentcorrection.Inaddition,throughmodificationsofthecontinuityequations,itshowsthatthevorticityoftheverticalshearvector(VVSV)isproportionalto-ω,theverticalvelocityinpcoordinates.Furthermore,ifthechangeofωinthehorizontaldirectionisneglected,thevorticityofthehorizontalvorticityvectorisproportionalto-ω.Whenωisunderafluctuatingstateintheverticaldirection,theupdraftoccurswhenthevectorofhorizontalvorticityrotatescounterclockwise;thedowndraftoccurswhenrotatingclockwise.ThevalidationresultindicatesthatthepresentmethodisgenerallybetterthantheverticalvelocitycalculatedbytheωequationusingthewetQ-vectordivergenceasaforcingterm,andtheverticalvelocitycalculatedbyutilizingthekinematicsmethodisfollowedbytheO’Brienmethodforcorrection.Theplus-minussignoftheverticalvelocityobtainedwiththismethodisnotcorrelatedwiththeintensityofdBZ,buttheabsoluteerrorincreaseswhendBZis>=40.Thismethoddemonstratesthatitisagoodreflectionofthedirectionoftheverticalvelocity.

  • 标签: 计算运动学 垂直速度 水平涡度 垂直运动 Q矢量散度 连续性方程
  • 简介:Inthispaper,theprincipleofmirrorimageisusedtotransformtheproblemofwavediffractionfromacircularcylinderinfrontoforthogonalverticalwallsintotheproblemofdiffractionoffoursymmetricincidentwavesfromfoursymmetricallyarrangedcircularcylinders,andthentheeigenfunctionexpansionofvelocitypotentialandGrafsadditiontheoremareusedtogivetheanalyticalsolutiontothewavediffractionproblem.Therelationofthetotalwaveforceoncylindertothedistancebetweenthecylinderandorthogonalverticalwallsandtheincidenceangleofwaveisalsostudiedbynumericalcomputation.

  • 标签: 波动衍射 圆柱体 正交垂直壁 镜面成像 海洋光学
  • 简介:Regularandirregularwaveforcesactingonverticalwallsarestudiedbyapreviouslydevelopednumericalmodel.Thecomputedwaveforcesarecomparedwiththeavailableexperimentaldatatoverifythenumericalmodel,andsatisfactoryagreementsareobtained.Thevariationofwaveforceswithincidentanglesandtheshapeofsimultaneouspressuredistributionareinvestigated,andthecomparisonsbetweennumericalresultsandGoda'spredictionsarealsocarriedout.Itisconcludedthatthemaximumwaveforcesactingontheunitlengthofverticalwallisofteninducedbytheobliquelyincidentwavesinsteadofnormallyincidentwaves,whileGoda'sformulamaybeinapplicableforobliquewaveincidence.Theshapeofsimultaneouspressuredistributionisnotsignificantlyinfluencedbyincidentangles,anditcanbefavorablypredictedbyGoda'sformula.WhenregularwaveheightsaretakenasthesameasirregularwaveheightH1%,theirregularwaveforcesPh,1%areslightlylargerthanregularwaveforcesinmostcases.

  • 标签: 波浪势力 垂直波 入射波 分布特点
  • 简介:Basedonthe2ndordercnoidalwavetheory,thecharactersofshallowwaterstandingwavesandtheiractiononverticalwallsarestudiedinthispaper.Thetheoreticalexpressionsofthewavesurfaceelevationinfrontofandthewavepressureontheverticalwallareobtained.Inordertoverifythetheoreticalresults,modeltestsweremadeintheStateKeyLaboratoryofCoastalandOffshoreEngineeringatDUT.Forthewavesurfaceelevationinfrontofthewallandthewaveforcesonthewallatthemomentwhenthewavesurfaceatthewallsurfacegoesdowntothebottomofthewavetrough,thecalculatedresultscoincidequitewellwiththeexperimentalresults.Forthewaveforcesonthewallatthemomentwhenthewavesurfaceatthewallsurfacegoesuptothetopofthewavecrest,thetheoreticalexpressionsaremodifiedbytheexperimentalresults.Fortheconvenienceofpracticaluse,calculationsaremadeforthewaveconditionswhichusuallyoccurinengineringpracticebyuseoftheinves

  • 标签: cnoidal WAVE VERTICAL WALL SHALLOW water
  • 简介:Likevaluechainandsupplychain,“industrialchain”becomesthefocusofattention.Theimplicationof“industrialchain”hasgainedalargerangeofextension.Itnotonlyexpressestheindustrial“chain”structureandrelationshipof“backandforward”inorderor“upanddown”indirection,butalsoitrepresentsaclusteroflargescaleoffirmsinanareaorcolony.Itisanetwork,oracommunity.Consequently,weconcludethat“industrialchain”isasynthesisofindustrialchain,industrialcluster,orindustrialnetwork.Inthisarticle,firstlywewilldistinguishindustrychainfromindustry.Anindustryisthecollectionoffirmsthathavethesameattribute,soanindustrycanbedefinedbyfirmcollectionofcertainattribute.Weindicatethatindustrialchainisakindofverticalandorderlyindustriallink.Itisdefinedaccordingtoaseriesofspecificproductorservicecreated.Secondlyweanalyzetheverticalorderlydefiinitionprocessfromtheaspectsofsocialdivisionoflaborandrequirementdivision,self-organizationsystem,andvalueanalysis.Non-symmetryanddependingonsystemorcommunityoflargescaleofindustrialunitsleadtoentireindustryto“orderly”structure.Ontheotherhand,thedraughtofdiversityandcomplexityofrequirementsimultaneouslyleadtoentireindustrytobemore“orderly”.Alongwithprocessesofself-organization,industrialwillappi'oachthestateofmoreorderlyandsteady,andconstantlymakeindustrialchainupgrade.Eachfirmorunit,whowillgainthevalue,hastoestablishchannelsofvalue,whichwecalled“industrialvaluechain”.Lastly,wediscusstheconsequenceofverticalandorderlydefinition,whichisexhibitedbyacertainrelationshipbody.Thetypicalformsofindustrialchainincludeindustrialcluster,strategyallianceandverticalintegrationetc.

  • 标签: 工业链条 整体套汇 垂直分解力 价值链
  • 简介:在那里存在,这被证明了在垂直的热之间的生气联合由使用线性热力学的狂暴的运输和垂直速度。这结果断言热的垂直部件狂暴的运输流动由垂直潜在的温度梯度的运输和垂直速度的联合运输组成。在这篇论文,垂直的热上的垂直速度的联合效果狂暴的交通被从大气的边界层使用观察数据决定联合系数的十字验证,并且狂暴的交通的一系列重要性质外面被打开。这些性质显示生气联合系数是尺寸的对数功能不太垂直的速度和尺寸更少高度,并且不仅与磨擦速度u*,有关而且到联合粗糙高度zW0和联合温度T垂直速度的W0。另外,仅仅当垂直速度大小遵循限制|W/u*时,功能关系建议那|≠1,并且在水平z然后,垂直速度导致生气联合的W0,垂直的热上的效果狂暴的运输流动。生气联合理论和试验性的结果提供挑战给传统的狂暴的K闭合理论和Monin-Obukhov类似理论。

  • 标签: 交叉耦合系数 湍流输送 热量垂直输送 垂直速度 线性热动力学 大气边界层
  • 简介:Discussionsarecarriedoutontheverticaldiscretizationofcurrentatmosphericmodels.Itispointedoutthatthereexistproblemsintheintegrationofthehydrostaticequationandthecomputationofverticaladvection,verticaldiffusionandsoon.Thensomepossiblewaysforsolvingoralleviatingthemaresuggested.Finally,thechoiceofverticalcoordinateandbasisfunctionsisdiscussed.

  • 标签: ATMOSPHERIC model VERTICAL DISCRETIZATION VERTICAL COORDINATE
  • 简介:切开技术的一时间对许多免费表面海洋模型普通。在内部、外部的模式的方程的不同截断错误要求数字调整保证算法正确地满足连续性方程并且保存tracers数量。princeton海洋模型(POM)使用了在每个内部时间步骤以外部速度调整内部速度的垂直平均数的一个简单方法。然而,由于Asselin时间过滤器,方法采用了阻止数字不稳定性,在POM使用的速度调整的方法能不再在内部模式保证连续性方程的满足,不过,一个特殊处理被用来与外部模式的联系内部模式的表面举起。错误被证明是在Asselin过滤器的系数的一个秒顺序术语。在数字模型的这个错误的一影响是在海地板的运动边界条件的失败。由一个地区性的实验和一个伪全球的实验,这个错误的大小被评估,并且这个错误的几敏感测试被执行。这个错误的特征被分析,二个其他的算法被建议减少错误。

  • 标签: 垂直速度 替代算法 聚甲醛 评估 普林斯顿海洋模式 连续性方程
  • 简介:在垂直的泵的吸入附近的流动结构试验性地并且数字地被调查以便在设计垂直的泵,没有失去高效,他们的安装区域在被要求最小的吸入的最佳形状获得一个指南。我们作为泵的形状的一个代表性的特征在吸入的扩大比率上集中我们的注意并且在泵性能上调查扩大比率的效果。如果我们为泵的安装需要的区域应该是最小的考虑,最佳扩大比率在1.1锝?.2变化,这被结束如果我们为泵的安装需要的区域应该是最小的考虑。关键词垂直的泵-吸入的形状-在吸入CLC数字TK7附近的流动结构

  • 标签: 立式泵 通风口外形 进口流动结构 导向索
  • 简介:Thispaperfirstdevelopstheapproachestodeterminethegeopotentialofthelocalmeansealevel,andtheninvestigatestheoffsetofthe1985verticaldatumsurfacedefinedbythemeansealevelofYellowSeaattheDagangTideGaugeinQingdaocityusingthedevelopedapproachesandGPS/levelingdata.Itshowsthatthegeopotentialofthelocalmeansealevelatthetidegaugeisequalto62636853.5±0.2m2*s-2andthatthe1985verticaldatumsurfaceis24.6±5.4cmabovethegeoidrealizedbythegeopotentialW0=62636856.0±0.5m2*s-2.

  • 标签: 全球定位系统 GPS 重力势 平均海平面 地方垂直基准点
  • 简介:Averticalantennaembeddedinearthwithconductivecoatinghasbeeninvesti-gatedbyemployingthemethodofintegralequation.ThistopicisavailabletoEM-MWD(Elec-tromagneticMeasurement-While-Drilling)system,whichisanewrealtimesystemfordrillingmeasurement.Undertheconditionthatthewavenumberoftheearthismuchlargerthanthatoftheair,acurrentintegralequationhasbeenderived.Afterthecurrentdistributionhavingbeendetermined,theelectricfieldstrengthontheearthsurfacehasbeenpredictedanditsdependencesontheoperatingfrequencyandthedepthofthewellhavebeendiscussedaswell.

  • 标签: VERTICAL ANTENNA Petroleum DRILLING Electric field
  • 简介:Insteady,solid-liquidtwo-phaseturbulentflows,thereexisttwotypicalpatternsoftheverticaldistributionofparticleconcentration.ThepatternIshowsamaximumconcentrationatanelevationabovethebed.ThepatternIIshowsanincreaseoftheparticleconcentrationdownwardoverthewholevertical,withthemaximumatthebed.MostofthetheoriesonparticleconcentrationdistributionhavebeendonewiththepatternII,anditislackofasuccessfultheorycovetingbothofthetwopatterns.Thispaperreviewstheparticledistributiontheories,includingthediffusiontheory,themixturetheory,theenergytheory,thesimilaritytheory,thestochastictheoryandthekinetictheory.Thekinetictheoryisalsoappliedtodescribetheverticaldistributionofparticleconcentrationinbothdiluteanddenseflows.

  • 标签: PARTICLE CONCENTRATION distribution DIFFUSION theory KINETIC
  • 简介:Thereexistthreetypesofconvolutionformulaefortheefficientevaluationofgravityfieldconvolutionintegrals,i.e.,theplanar2Dconvolution,thespherical2Dconvolutionandthespherical1Dconvolution.Thelargestdrawbackofboththeplanarandthespherical2DFFTmethodsisthat,duetotheapproximationsinthekernelfunction,onlyinexactresultscanbeachieved.Apparently,thereasonisthemeridianconvergenceathigherlatitudes.Asthemeridiansconverge,theΔφ,Δλblocksdonotformarectangulargrid,asisassumedin2DFFTmethods.Itshouldbepointedoutthatthemeridianconvergencenotonlyleadstoanapproximationerrorinthekernelfunction,butalsocausesanapproximationerrorduringtheimplementationof2DFFTincomputer.Inordertomeettheincreasingneedforprecisedeterminationoftheverticaldeflections,thispaperderivesamorepreciseplanar2DFFTformulaforthecomputationoftheverticaldeflections.Afterhavingmadeadetailedcomparisonbetweentheplanarandthespherical2DFFTformulae,wefindoutthemainsourceoferrorscausingthelossinaccuracybyapplyingtheconventionalspherical2DFFTmethod.Andthen,amodifiedspherical2DFFTformulaforthecomputationoftheverticaldeflectionsisdevelopedinthispaper.Aseriesofnumericaltestshavebeencarriedouttoillustratetheimprovementmadeupontheoldspherical2DFFT.Thesecondpartofthispaperistodiscusstheinfluencesofthesphericalharmonicreferencefield,thelimitedcapsize,andthesingularintegralonthecomputationoftheverticaldeflections.TheresultsoftheverticaldeflectionsoverChinabyapplyingthespherical1DFFTformulawithdifferentintegrationradiihavebeencomparedtotheastro-observedverticaldeflectionsintheSouthChinaSeatoobtainasetofoptimumdeflectioncomputationparameters.

  • 标签: FFT SPECTRAL method DEFLECTION COMPUTATION
  • 简介:Ananalysissolutionofrateequationisderivedforverticalcavitysurface-emittinglasers.BasedontheenhancedspontaneousemissioncausedbyVCSELsandinfluenceofnonradiativerecombination,therelationbetweenoutputpropertiesandstructuralparametersofmulti-quantumwells(MQWs)isobtanined.Itwasfoundthatthecharacteristiccurveofa"thresholdless"laserisstronglynonradiativedepopulation-dependent.Whenthenonradiativedepopulationisnozero,thelight-currentcharacteristicisnotlinearlyevenforanidealclosedmicrocavity.Thelightoutputisincreasedbytheenhancedwellnumberandbythereducedwidth.Inparticular,alowerthresholdcurrentdensityforMQWsstructureintheshortcavityisrealizedbyus,meanwhilethesharpnessofthevariationdependsonspontaneousemissionfactor.

  • 标签: 速率方程式 自然发射系数 结构参数 垂直空腔激光器 MQWs VCSELS
  • 简介:Threetyphoons,Goni,MorakotandEtauwhichweregeneratedinWesternPacificin2009,aresuccessfullysimulatedbytheWRFmodel.Thehorizontalandverticalvorticityandtheirinteractionareanalyzedanddiagnosedbyusingthesimulationresults.Itisshownthattheirresultantvectorshadafixedpatternintheevolutionprocessofthethreetyphoons:Thehorizontalvorticityconvergedtothetropicalcyclone(TC)centerbelow900hPalevel,flowedoutfromitataround900to800hPa,andflowedinbetween800hPaand700hPa.Ifmultiplemaximumwindspeedcentersshowedup,thehorizontalvorticityconvergedtothecenterofthetyphoonbelowthemaximumwindspeedcenteranddivergedfromtheTCcenterabovethemaximumwindspeedcenter.Atlowlevels,thethreetyphoonsinteractedwitheachotherthroughverticalcirculationgeneratedbythevortextube.Thiscirculationwasmainlygeneratedbytheeastwardorwestwardhorizontalvorticityvectors.Cloudsandprecipitationweregeneratedontheascendingbranchoftheverticalcirculation.ThevortextubesoftenflowedtowardthesouthwestoftherightTCfromthenortheastoftheleftTC.Accordingtothefullvorticityequation,thehorizontalvorticityconvertedintotheverticalvorticitynearthemaximumwindspeedcenterbelow850hPalevel,andtheperiodofmostintenseconversionwasconsistentwiththeintensificationperiodofTC,whilethevorticityadvectionwasagainsttheintensification.Theverticalvorticityconvertedintothehorizontalvorticityfrom800hPato600hPa,andthewindspeeddecreasedabovethemaximumwindspeedregionatlowlevels.

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