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382 个结果
  • 简介:Thisstudyproposesanewidentificationalgorithmabouttheadmittancefunction,whichcanestimatethefullsetofsixaerodynamicadmittancefunctionsconsideringcrosspowerspectraldensityfunctionsabouttheforcesandtheturbulencecomponents.ThemethodwasfirstnumericallyvalidatedthroughMonteCarlosimulations,andthenadoptedtoestimatetheaerodynamicadmittanceofastreamlinedbridgedeck.Theidentificationmethodwasfurthervalidatedthroughacomparisonbetweenthenumericalcalculationandwindtunneltestsonamovingbridgesection.

  • 标签: aerodynamic ADMITTANCE FUNCTION streamlined box bridge
  • 简介:Experimentsarereportedontheeffectsofflowintensity,obstaclealignmentandcross-sectiongeometryontheequilibriumscourdeptharoundabutments.Theeffectofflowintensitywasstudiedforclearwaterflowconditions,theobstaclealignmentwasstudiedforawiderangeofanglesoftheobstaclewiththeflowdirection,andtestsonthecross-sectiongeometryapplyonlytothecasewheretheabutmentextendsintothemainchannelofacompoundcross-section(two-stagechannel).Thechannelbankandfloodplainwerebuiltupwithsand.Thehypothesisofzeroscourforflowvelocitiessmallerthanapproximately50%ofthethresholdvelocityforthebeginningofmotionintheapproachingflowcannotberejected;maximumscouroccursforobstaclesprotrudingatrightanglefromthecross-sectionwalls,thereductionbeingsmallwhenobstaclespointupstream;comparedwithrigidbanks,thescourdepthseemstobesignificantlyreducedwhenchannelbankandfloodplainareconstitutedofalluvialmaterial.

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  • 简介:Rainbow是个神奇的自然现象,它的出现总是给人惊喜和愉悦,所以RainbowBridge将是一个传递惊喜和欢乐的桥梁。通过RainbowBridge,你可以把你的祝福送到每个角落。你的父母、你的老师、你的朋友将在这里接收到你对他们的关心和帮助。

  • 标签: 小学 英语学习 学习方法 阅读
  • 简介:Rainbow是个神奇的自然现象,它的出现总是给人惊喜和愉悦,所以RainbowBridge将是一个传递惊喜和欢乐的桥梁。

  • 标签: 小学 英语 课外阅读 阅读材料
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  • 简介:THESEoldZhuangminorityfarmers'houseshavethreestories-pigs,hensandotherfarmanimalsarekeptonthefirstfloor,familymembersliveonthesecondandgrainandcornarestoredonthethird.'It'saprettysmartdesignbecauseit

  • 标签: 中国 农业信息化 信息技术 农业经济
  • 简介:ThereisariverflowinginfrontofBainamVillageinDeqengTownofDarzeCounty.Becauseschools,infirmaries,supplyandmarketingcooperativesandmostofthefarmlandareallontheothersideoftheriver,anyonewhowantedaccesshadtoundertakeaninconvenient12-kindetour.Mattersbecameevenworseintherainyseason,whenthewaterlevelrose.

  • 标签: 达孜县 桥梁 奉献精神 退休教师 人格精神
  • 简介:Thelogicalderivativesofp-adiccopy-shiftandshift-copygeneralizedBridgefunctionsaregiveninthispaper.Whenpequals2,theyareexactlythelogicalderivativesofnaturalorderingcopy-shiftandcopy-shiftBridgefunctions.

  • 标签: 矿气 生产
  • 简介:Thispapersummarizesthedesignequationsforlocalscourdeptharoundbridgeabutmentsasproposedbydifferentinvestigators,andalsothedifferentfactors,affectingthescourdepth.Methodsfortheestimationoflocalscourdepthbasedondimensionalanalysisarealsopresented.Thedesignmethodsbasedonempiricalrelationssuchasflowdepth,flowintensity,sedimentcharacteristics,abutmentsshapeandsize,alignment,andapproachchannelgeometryarealsodiscussed.Sinceclear-waterscouristhemaximumscourdepth,theequationforclear-waterscourisrecommendedforthecomputationoflocalscourdeptharoundbridgeabutmentsforuniformlyandnon-uniformlygradedsediments.

  • 标签: Local scour Bridge abutments FLOOD plain
  • 简介:Anintegratedcouplingelementconsideringwheel-railinterfaceforanalyzingthedynamicresponsesofvehicle-rail-bridgeinteractionsystemwithanon-uniformcontinuousbridgeispresented.Thegoverningequationsoftheinteractionsystemareestablishedfirst,andthesolutionprocedureandassemblymethodofthecouplingelementaredemonstrated.Finally,theaccuracy,efficiencyandfunctionoftheintegratedcouplingelementaretestedusingtwonumericalexamples.Theinfluencesofdifferentcombinationsofrailandbridgeelementlengthinthecouplingelementonthesolutionareinvestigated,andtheeffectsofdifferentrailirregularitiesonthedynamicresponsesarediscussed.

  • 标签: 耦合单元 统集成 非均匀 连续梁桥 元件 相互作用系统
  • 简介:Tosystematicallystudythevehicle–bridgecoupleddynamicresponseanditschangerulewithdifferentparameters,avehiclemodelwithsevendegreesoffreedomwasbuiltandthetotalpotentialenergyofvehiclespacevibrationsystemwasdeduced.Consideringthestimulationofroadroughness,thedynamicresponseequationofvehicle–bridgecoupledsystemwasestablishedinaccordancewiththeelasticsystemprincipleoftotalpotentialenergywithstationaryvalueandthe‘‘set-in-right-position''rule.Onthebasisoftheself-compiledFortranprogramandbridgeengineering,thedynamicresponseoflongspancontinuousgirderbridgeundervehicleloadwasstudied.Thisstudyalsoincludedthecalculationofvehicleimpactcoefficient,evaluationofvibrationcomfort,andanalysisofdynamicresponseparameters.Resultsshowtheimpactcoefficientchangeswithlanenumberandislargerthanthevaluecalculatedbythe‘‘generalcodefordesignofhighwaybridgesandculverts(China)''.TheDieckmannindexofbridgevibrationisalsorelatedtolanenumber,andthevibrationcomfortevaluationisgoodinnormalconditions.Therelevantconclusionsfromparametricanalyseshavepracticalsignificancetodynamicdesignanddailyoperationoflong-spancontinuousgirderbridgesinexpressways.Safetyandcomfortareexpectedtoimprovesignificantlywithfurthercontrolofthevibrationofvehicle–bridgesystem.

  • 标签: 大跨度连续梁桥 耦合系统 动力响应 数值分析 FORTRAN程序 舒适性评价