简介：Weconductedacomprehensivestudytoinvestigatetheaerodynamiccharacteristicsandforcegenerationoftheelytraofabeetle,Allomyrinadichotoma.Ouranalysisincludedwindtunnelexperimentsandthree-dimensionalcomputationalfluiddynamicssimulationsusingANSYS-CFXsoftware.Ourfirstapproachwasaquasi-staticstudythatconsideredtheeffectofinducedflappingflowduetotheflappingmotionofthefore-wings(elytra)atafrequencyofaround30Hzto40Hz.Thedihedralanglewasvariedtorepresentflappingmotionduringtheupstrokeanddownstroke.Wefoundthatanelytronproducespositiveliftat0°geometricangleofattack,negativeliftduringtheupstroke,andalwaysproducesdragduringboththeupstrokeanddownstroke.Wealsofoundthattheliftcoefficientofanelytrondoesnotdropevenataveryhighgeometricangleofattack.Forabeetlewithabodyweightof5g,basedonthequasi-staticmethod,thefore-wings(elytra)canproduceliftoflessthan1%ofitsbodyweight.

简介：QuestionsconcerningthefunctionalroleofthehollowregionofthebutterflyPyrameisatalanta(L.)scaleareexperimentallyinvestigated.Attentionwasinitiallydirectedtothisproblembyobservationofthecomplexmicrostructureofthebutterflyscaleaswellasotherstudiesindicatinghigherliftonbutterflywingscoveredwithscale.Theaerodynamicforcesweremeasuredfortwooscillatingscalemodels.ResultsindicatedthattheaircavityofanoscillatingmodelofthePyrameisatalanta(L.)scaleincreasedtheliftbyafactorof1.15andreducedthedampingcoefficientsbyafactorof1.38.Themodificationoftheaerodynamiceffectsonthemodelofbutterflyscalewasduetoanincreaseofthevirtualairmass,whichinfluencedthebody.Thehollowregionofthescaleincreasedthevirtualairmassbyafactorof1.2.Thevirtualmassofthebutterflyscalewiththehollowregionwasrepresentedasthesumofairmassoftwoimaginarygeometricalfigures:acircularcylinderaroundthescaleandaright-angledparallelepipedwithinthehollowregion.TheinteractionmechanismofthebutterflyPyrameisatalanta(L.)scalewithaflowwasdescribed.Thisnovelinteractionmechanismexplainedmostgeometricalfeaturesoftheairpermeablebutterflyscale(invertedV-profileoftheridges,nozzleofthetipedge,hollowregion,andopeningsoftheupperlamina)andtheirarrangement.