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191 个结果
  • 简介:Proceedingfromtheeigenvalueequationofthenormalmodeinhomogeneousshallowwater,wederiveseveralformulaecalculatingthemodeattenuationandgroupvelocity,andcomparetheiraccu-racybymeansofnumericalresults.Thepaperespeciallydiscussestheattenuationandthegroupve-locityofcriticalmodeinaPekerischannelandshowsthatingeneral,theattenuationandthegroupvelocityofthecriticalmoderespectivelyarelessthantheabsorptionandthesoundspeedinthebot-tom.Therefore.theKornhauser,Raney,WestonTindle‘sconclusionsaremodifiedthattheattenuationandthegroupvelocityofthecriticalmodeareexactlyequaltotheabsorptionandthesoundspeedinthebottom,respectively.

  • 标签: calculating EXACTLY ATTENUATION FORMULAE simplified EIGENVALUE
  • 简介:BasedontheEMMSmodel,thelocalslipvelocitybetweengasandsolidissystematicallyanalyzedandatheoreticalcorrelationoflocalslipvelocitywithlocalvoidageforadownerisderivedasfollows:us(r)/ut=D8/7(1-εmf)-2/7[1-ε(r)/ε(r)]8/7ε(r)47/14ε(r)-εmf/ε(r).Usingthiscorrelation,thelocalgas-solidslipvelocityinadowneriscalculated.Thecalculatedresultsarewellconsistentwithexperimentaldata.Inaddition,thevariationofthelocalslipvelocitywithitscorrespondingsolidholdupisalsodiscussed.

  • 标签: EMMS模型 局部滑移速度 系统分析 空隙度 流体力学 理论分析
  • 简介:Debrisflowsinnaturegenerallyfallintothreegroupsdistinctintheirgraincomposition:water-stoneflow,orsub-viscousdebrisflow,dominatedbycoarsegrains;muddyflow,dominatedbyfinegrains;andviscousdebrisflowcomposedofgrainsinlargerange.Liquid-phasevelocityandsedimentarydeliveryresistanceofsub-viscousdebrisflowhavebeendiscussedbasedonthecompositioncharactersofsub-andhigh-viscousdebrisflows.Itisrevealedthatthepresenceoffinegrainsplaysavitalroleinaffectingresistanceandaveragevelocity,particularlywhenthevolumefractionofgrainsintheflowisrelativelyhigh,i.e.Sv>0.45.Grain-sizedistributionofviscousdebrisflowischaracterizedbyabimodalcurve,whichexplainsthepropertieslikehighdensityandlowresistancegradientofdebrisflows.Acalculationformulaisfinallyputforward,whichhastosomeextentovercomelocalitylimitsandachievedagoodagreementwiththefieldobservationsofdebrisflowsinSouthwestChina.

  • 标签: Sub-viscous DEBRIS flow Viscous DEBRIS flow Grain composition Concentration Velocity
  • 简介:速度体积处理(VVP)单个Doppler雷达的检索是能被用来获得许多风参数的一个有效方法。由于从方程的系数产生容易没被解决的一个性恶的矩阵的问题,然而,VVP方法没在操作足够地并且有效地被使用。在这篇论文,一个改进计划,基于原来的方法,SVVP(处理的步速度体积)被建议。改进算法通过一个逐步的过程检索风地的每组部件,它克服一个性恶的矩阵的问题,它当前限制VVP方法的申请。就算分析卷是很小的,在一个六参数的模型的变量能被检索。另外,在传统的方法存在的错误的来源和顺序被分析。改进方法被用于真实盒子,它证明它是柔韧的并且有能力获得本地对流系统的风地结构。它对学习暴风很有用。

  • 标签: 气象雷达 多普勒雷达 雷达数据处理 高速批处理方法 病态矩阵 风参数
  • 简介:UsingpureSwavefittingmethod,westudiedtheshearwavevelocitystructuresundertheOrdosblockanditseasternandsouthernmarginalareas.TheresultsshowthatthevelocitystructurebeneathYulinstationintheinteriorofOrdosblockisrelativelystable,wherenoapparentchangebetweenhighandlowvelocitylayersexistsandtheshearwavevelocityincreasessteadilywiththedepth.Thereisa12kmthicklayeratthedepthof25kmunderthisstation,withanSwavevelocity(Vs=3.90km/s)lowerthanthatatthesamedepthinitseasternandsouthernareas(Vs≥4.00km/s).ThecrustundertheeasternmarginofOrdosblockisthickerthanthatoftheYulinstation,andthevelocitystructuresalternatebetweenthehighandIowvelocitylayers,withmorelowvelocitylayers.Ithasthesamecharacteristicashavinga10km-thicklowvelocitylayer(Vs=3.80km/s)inthelowercrustbutburiedatadepthofabout35km.Moreover,westudiedtheVi/VsratioundereachstationincombinationwiththeresultofPwavevelocityinversion.Theresultsshowthat,theaveragevelocityratiooftheYulinstationattheinteriorofOrdosblockisonly1.68,withaverylowratio(about1.60)intheuppercrustandastableratioofabout1.73inthemidandlowercrust,whichindicatesthemediaunderthisstationishomogenousandstable,beinginastateofrigidity.ButatthestationsintheeasternandsouthernmarginsoftheOrdosblock,severallayersofhighvelocityratio(about1.80)havebeenfound,inwhichtheaveragevelocityratiounderKelanandLishistationsattheeasternmarginissystemicallyhigherthanthatofthegeneralelasticalbodywaves(1.732).Thisreflectsthatthecrustunderthemarginalareasismoreactiverelatively,andothermaterialsmayexistintheselayers.Finally,wediscussedtherelationshipamongearthquakes,velocitystructuresbeneathstationsandfaults.

  • 标签: 鄂尔多斯板块 S波 速度结构 地质运动 地震
  • 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:Basedonthehydrodynamicalfeatureandthetheoreticalvelocityprofilesoftidalflowandwind-inducedflowinshal-lowsea,acomputationalmodelisestablishedforthefirsttime,whichcanseparateobservedvelocityintotidalvelocityandwind-inducedvelocitybyuseoftheleastsquaremethod.Withthemodel,notonlythesurfacevelocitiesoftidalflowandwind-inducedflowareobtained,butalsothebedroughnessheightisdeterminedandthewindvelocityabovethewa-tersurfaceisestimated.Forverificationofthemodel,theobservedvelocityintheYellowRiverEstuaryandthelaborato-rytestisseparated,thenitisappliedtotheYangtzeRiverEstuary.Alltheresultsaresatisfactory.Theresearchresultsshowthatthemodelissimpleinmethod,feasibleinprocessandreasonableinresult.Themodelisavalidapproachtoanalysisandcomputationoffielddata,andcanbeappliedtoseparatetheobservedvelocityinshallowsea;atthesametime,reasonableboundaryconditionsofthesurfaceandbottomcanbeobtainedfortwo-andthree-dimensionalnumericalsimulation.

  • 标签: SHALLOW SEA VELOCITY profile TIDAL fiow
  • 简介:在这篇文章,七个月周围的噪音数据和10个事件从Ningxia在七个数字车站记录了()控制来源爆炸数据记录了由的地区性的地震网络和5500-t15暂时并且7个永久地震车站被用来测量基本模式瑞利波浪的分散曲线。学习区域与0.1杳慲散眠被划分成格子吗?

  • 标签: 速度分布 瑞利波 宁夏 RAYLEIGH波 波群 区域地震台网
  • 简介:把早期的运动基于不一致的沉积的机制,拖强迫并且高举力量系数表情为不一致的床材料暴露和靠近的排列状态被提出。不一致的沉积的早期的速度公式然后被建立。公式结构合理、好,这被显示出不一致的沉积的粒子比一样缩放一致粒子的是更困难的设定进运动,而更粗糙的粒子更容易比他们的一致等价物设定进运动。公式的有效性由地和实验数据被验证。

  • 标签: 初始速度 沉淀物 物质分配 河道处理
  • 简介:Watermotioninestuarinewatersistheresultoftheactionofvariousdynamicfactors.Firstly,basedonthehydrodynamiccharacteristicsinestuarinewaters,neglectingthenonlineareffectsofvariousflowhydrodynamicfactors,thelogarithmvelocityprofileoftidalcurrentandthecubicvelocityprofileofHansenandRattray(1965)madeforlinearsuperpositionatasenseoffirstorder,anewmodelforvelocityprofileinestuarinewatersisestablished.Then,byintroducingtheleastsquaremethodcombinationofenumeration,thevelocityprofiledataofwind-drivencurrentmeasuredinthelaboratoryandthatobservedattheNorthandtheSouthBranchesoftheYangtzeEstuaryareverifiedandcomparedwithotherformulas,allwithsatisfactoryresults.Theresultsshowthatthenewmodelnotonlyconsiderstheinfluencesofvariousdynamicfactors,suchastide,windforce,run-offanddensitypressurewithhighaccuracy,butalsoprovidesreasonableboundaryconditionsonthebottomforhydrodynamicsnumericalsimulationinestuarinewaters.Thereby,theaccuracyandcredibilityofnumericalcomputationandpredictionofwaterflowareimproved.Theresearchistheoreticallyimportantfortheestuarinehydrodynamics.

  • 标签: 水域 河口 流速分布 非线性效应 流速剖面 动力学因素
  • 简介:Adetailthree-dimensionalPwavevelocitystructureofBeijing,TianjinandTangshanarea(BTTarea)wasdeterminedbyinvertinglocalearthquakedata.Intotal16048Pwavefirstarrivaltimesfrom16048shallowandmid-depthcrustalearthquakes,whichoccurredinandaroundtheBTTareafrom1992to1999wereused.ThefirstarrivaltimesarerecordedbyNorthernChinaUnitedTelemetrySeismicNetworkandYanqing-HuailaiDigitalSeismicNetwork.Hypocentralparametersof1132earthquakeswithmagnitudeML=1.7~6.2andthethree-dimensionalPwavevelocitystructurewereobtainedsimultaneously.TheinversionresultrevealsthecomplicatedlateralheterogeneityofPwavevelocitystructurearoundBTTarea.Thetomographicimagesobtainedarealsofoundtoexplainotherseismologicalobservationswell.

  • 标签: 京津唐地区 地震波 P波速度结构 数字遥测地震台网 地震观测 地震活动性
  • 简介:Inthispaper,wefirstlyanalyzethe"3,400traveltimetable"usedforalongtimeinXinjiangSeismologicalNetworktoobtainthevelocitystructuremodelsinaccordwiththetablebyfitting.ThenwefitthevelocityofallseismicphasesrecordedinXinjiangregioninJanuary2009~December2013.Simulationanalysisisdoneonthereliabilityandstabilityofthevelocities,andaconceptisproposedforbuildingsubareacrustalvelocitymodelsaccordingtopartitioningofseismicclusterregions.ThecrustalvelocitymodelsuitablefortheYutianareaisfittedwiththedataofallphasesofseismiceventswithinaradiusof1°aroundthe2014YutianM_S7.3earthquakesinceJanuary2009,andthemodelisappliedtotherelocationoftheYutianM_S7.3earthquakeanddeterminationoffocaldepthsoftheearthquakesequence.

  • 标签: 地壳速度模型 新疆地区 地震台网 内区 结构模型 仿真分析
  • 简介:Thepresentpaperisfocussedontheeffectsofviscousandturbulentshearstressesonbothverticalvelocityandconcentrationdistributionsinlargesuspensionofsands.Whentheflowcarrieslargeamountofsedimentsinsuspension,thepropertiesoffluidmixturearechangedintermsofmodifiedviscosity,densityandfallvelocity,andhencetheflowcharacteristics.Theoreticalmodelshavebeendevelopedforbothvelocityandconcentrationprofiles,takingintoaccounttheviscousandturbulentshearstresses,whicharethefunctionofvolumetricconcentration.Comparisonoftheoreticalmodelswithexperimentaldatarevealsthat(i)themodifiedvelocityandconcentrationprofilesagreewellwiththeobserveddataforhighsuspension,(ii)thehigherthesedimentsuspension,thesmallerthevonKarmanconstant,and(iii)sedimentdiffusioncoefficientislessthanmomentumdiffusioncoefficientforfinesandsinsuspension.

  • 标签: SEDIMENT suspension Viscosity Turbulent shear stress Hindered settling Velocity and
  • 简介:为了提供指令因为推进器的计算用身体在壳推进器相互作用的学习导致了速度,强迫途径,三个方法被用来计算推进器导致的速度:1)自我推进测试的平均Reynolds的海军司烧(RANS)模拟,2)推进器的RANS模拟开的水测试,并且3)推进器的动量理论。从开始的二个方法的结果对试验性的数据被验证估计计算流动领域的精确性。戳身份方法被采用获得进展速度,它然后被用来导出推进器来自全部的速度地的导致的速度。开始的二条途径计算的结果是靠近的,当那些显著地从动量理论被过高估计时。介绍结果能证明为用身体力量途径的自我推进的另外的计算有用。

  • 标签: 速度计算 诱导速度 动量理论 RANS 螺旋桨 NAVIER-STOKES