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变异卵圆形凹坑非光滑表面的气动摩擦减阻研究（英文）.docx

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变异卵圆形凹坑非光滑表面的气动摩擦减阻研究（英文） Title:AerodynamicFrictionReductionStudyonNon-smoothSurfacewithEllipticalDepressions Abstract: Aerodynamicfrictionreductionisofgreatsignificanceinmanyaspectsofengineeringandtransportation.Inthisstudy,weinvestigatetheeffectofellipticaldepressionsontheaerodynamicfrictionreductionofnon-smoothsurfaces.Theexperimentswereconductedinawindtunnelwithdifferentflowvelocitiesandanglesofattack.Theresultsindicatethattheellipticaldepressionsonthenon-smoothsurfacecansignificantlyreducetheaerodynamicfrictiondrag.Themaximumreductionindragcoefficientwasfoundtobeupto20%atanangleofattackof10degreesandaflowvelocityof15m/s.Thereasonforthefrictionreductionisattributedtothevortexsheddingandturbulencecontrolcausedbytheellipticaldepressions.Thestudyprovidesnewinsightsintothedesignofaerodynamicsurfaceswithdepressedfeaturesforfrictionreduction. Introduction: Aerodynamicfrictionreductionisanimportantissueinvariousfieldsofengineeringandtransportation.Highaerodynamicfrictioncanleadtoincreasedfuelconsumption,unstableflightconditions,andreducedoverallperformance.Surfacemodificationhasbeenprovedtobeaneffectivewaytoreducetheaerodynamicfrictionofsurfaces.Manystudieshavebeenconductedtoinvestigatetheeffectofsurfacegeometryonthefrictionreductionofsmoothsurfaces.However,theeffectofnon-smoothsurfaceswithdepressedfeaturesontheaerodynamicfrictionreductionisstillnotwellunderstood. Ellipticaldepressionsareonetypeofnon-smoothsurfacefeaturesthathavebeenobservedinnature.Forexample,theskinofsharkshasanon-smoothsurfacewithnumeroussmalldepressions.Ithasbeenreportedthatthedepressionsonsharkskincanreducethefrictiondragbycontrollingtheboundarylayerandflowseparation.Inspiredbythenaturalexamples,weinvestigatetheeffectofellipticaldepressionsontheaerodynamicfrictionreductionofnon-smoothsurfaces. ExperimentalSetupandProcedures: Theexperimentswerecarriedoutinawindtunnelwithaclosedtestsectionof2m×2m×4m.Thetestsectionwasequippedwithaturbulencegeneratortoensureafullydevelopedturbulentflow.Anon-smoothsurf