Dynamic soaring in shear flow

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1、nsoredby-AmericanInstituteofAeronauticsandAstronautics(AIAA)vMassachusettsInstituteofTechnology(MIT)SoaringSocietyofAmerica(SA).-DYNAMICSOARINGINSHEARFLOW0EWQ'QCAMBRIDGE,MASSACHUSETTS/SEPTEMBER11-13,1974a.-

2、mericanlnslilvlcofAeronauticsandAstronaulics.129OAveniieofheAincricas.NewYork,N.Y.10019.DYNAMICSOARINGINSiiEARFLOW*FerdinandHendriks**IBMThomasJ.WatsonResearchCenterYorktownHeights,NewYorkAbstractmuchofthesmoothnessandgracethatobser-versofdynamicsoaringInnature

3、report.ThesubjectofextractionofenergybyAnotheravenueofmathematicalsimplifica-glidersfromnon-uniformflowshasalwaystionistoaseumethatthegliderisex-beencontroversial.Severaloutstandingtremely"clean"andthatitsmotionneverauthorshavecommentedontheproblem,deviatesmuchf

4、romahorizontalplane,inamostlyduringthetimewhendynamicsoaringsensemademorepreciselater.Theemphasis(DS)seemedtobepromisinginthemain-isalwaysonhowtostayaloftregardlessofstreamofprogressinaviation.thedriftoftheglider.Inthiswork,thegliderdriftsontheaveragewiththemean

5、Today,DShasasmallplaceintheorni-windspeedatitsaverageverticalposition..thologicalliterature,especiallywheretheItisinprinciplepossibletomakeprogressflightoflargealbatrossesisconcerned,intothewindbutthiscaseismorediffi-butsufficientproofthatDSexistsisculttoanalyse

6、.stilllacking.11.MathematicalTreatmentThepresenttreatmentdealswithanap-proximatemathematicaldescriptionoftheLetthemassofthegliderbem,itswingmotionofaRlider,modeledasacontrolledarea5,theairdensityeandtheaccelera-masspointfiyinginauniformlyshearedtionofrrravitvE.I

7、naninertialframethewind.Themotionconsideredisthree-position-ofthkglidershallber(t),wheredimensionalandatzerothorder(inaper-tisthetime;thewindhasaverticalshearturbationschemewherethedragcoefficientofmagnitude(dU/dz)di,.IfU(z)istheissmall)itismerelvahorizontal.cir

8、-windspeed,therela?,IGewind"seen"bythecularmotionflownat"constantanglkofgliderisV(t):attackandatarbitrarybutfixedbankwangle.AtfirstordertheequationofmotionisaforcedMa