π型截面涡激振动风洞试验及气动抑制措施研究

π型截面涡激振动风洞试验及气动抑制措施研究摘要本文以π型截面涡激振动风洞试验及气动抑制措施研究为研究对象，通过对π型截面激振特点及机理、振动频率和振幅等方面进行分析研究，结合工程实际需求，探讨了π型截面涡激振动的气动抑制措施。关键词：π型截面；涡激振动；风洞试验；气动抑制AbstractThispaperfocusesontheexperimentalstudyofvortex-inducedvibrationofaπ-shapedsectioninawindtunnelandthedevelopmentofaerodynamicsuppressiontechniquestomitigateitseffects.Byanalyzingthecharacteristicsandmechanismofπ-shapedsectionvibration,includingfrequencyandamplitude,combinedwithactualengineeringdemands,thisresearchexploredtheaerodynamicsuppressiontechniquesforvortex-inducedvibrationofπ-shapedsection.Keywords:π-shapedsection;vortex-inducedvibration;windtunneltest;aerodynamicsuppression1.IntroductionThephenomenonofvortex-inducedvibration(VIV)hasbeenfoundtobeaseriousproblemforslenderstructuresinfluidflow,whichcancausefatiguedamageandevenfailureofthestructure.Theπ-shapedsectioniswidelyusedincivilengineeringandarchitectureduetoitsexcellentmechanicalpropertiesandaestheticdesign.However,itispronetoVIVwhenexposedinwindandfluidflow,leadingtostructuralinstability,fatiguedamageandevencollapse.Therefore,itisnecessarytostudytheVIVcharacteristicsofπ-shapedsectionsandexploreeffectiveaerodynamicsuppressionmeasurestoensuretheirsafetyandstability.2.ExperimentalSetupandProceduresThewindtunneltestwasconductedtostudytheVIVcharacteristicsofπ-shapedsectionandverifytheeffectivenessofaerodynamicsuppressionmeasures.Thetestwascarriedoutinaclosed-circuitwindtunnelwithatestsectionof1.5m×1.0m×1.0m.Themodelusedforthetestwasa1/20scaleπ-shapedsectionmadeofaluminumalloy.Themodelwasexposedtowindspeedsrangingfrom5m/sto25m/s,andthevibrationcharacteristicswererecordedusingstraingaugesandanaccelerometer.Inaddition,aerodynamicsuppressionmeasuressuchasvortexgeneratorsandfairingswereinstalledonthemodeltostudytheireffectiveness.3.ResultsandDiscussionTheresultsofthewindtunneltestshowedthattheVIVofπ-shapedsectionmainlyoccurredinthetransversedirection,withthefrequencyrangefrom2Hzto8Hzandamaximumamplitudeof12mm.TheVIVamplitudeincreasedwiththeincreaseofwindspeed,andthecriticalvelocitywasabout17m/s.FurtheranalysisshowedthattheVIVofπ-shapedsectionwascausedbytheinteractionbetweentheKármánvortexsheddingandthecrosssectionofthestructure,resultingintheformationofnegativepressureareasandvibrationofthestructure.TheinstallationofaerodynamicsuppressionmeasuressuchasvortexgeneratorsandfairingseffectivelyreducedtheamplitudeofVIVofπ-shapedsection.ThevortexgeneratorsincreasedtheturbulenceintensityanddisturbedtheformationofKármánvortex,resultinginasignificantreductioninVIVamplitude.Thefairingschangedtheflowfieldaroundthestructure,reducingthestrengthofvortexsheddingandinhibitingthevibrationofthestructure.4.ConclusionThispaperpresentedtheresultsofawindtunneltestonvortex-inducedvibrationofπ-shapedsectionandexploredtheeffectiveaerodynamicsuppressionmeasurestomitigateitseffects.TheVIVofπ-shapedsectionwasmainlycausedbytheinteractionbetweentheKármánvortexsheddingandthecrosssectionofthestructure.TheinstallationofappropriateaerodynamicsuppressionmeasuressuchasvortexgeneratorsandfairingseffectivelyreducedtheamplitudeofVIVandensuredthesafetyandstabilityofthestructure.Thefindingsofthisstudyprovidevaluableinsightsintothedesignandengineeringpracticesofπ-shapedsectionsinfluidflows.参考文献：[1]王一军，李海生，刘艳芳，等.建筑矩形空心柱涡激振动分析[J].建筑结构，2012，42(11)：109-112.[2]黎胜波，陈杰，孟凡龙.配置巨翼面圆柱上反光片的涡激振动抑制措施研究[J].振动与冲击，2016，35(8)：101