Numerical Simulation of Unsteady Flow Around Forward Flight Helicopter with Coaxial RotorsWord文件下载.docx
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Numerical Simulation of Unsteady Flow Around Forward Flight Helicopter with Coaxial RotorsWord文件下载.docx
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Thispaperdescribesanonsmoothoptimizationtechniqueallowingtodesignalateralflightcontrollawforahighlyflexibleaircraft.Flexiblemodesandhigh-dimensionalmodelsposeamajorchallengetomoderncontroldesigntools.Itisshownthatthenonsmoothapproachofferspotentandflexiblealternativesinthisdifficultcontext.Morespecifically,theproposedtechniqueisusedtoachieveamixoffrequencydomainaswellastime-domainrequirementsforasetofdifferentloadconditions.
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1.Introduction
2.Multi-objectivecontrollerdesignvianonsmoothoptimization
3.Nonsmoothoptimizationtechnique
4.Applicationtolateralflightcontroldesignofahighlyflexibleaircraft
4.1.Problemdescription
4.2.Nonsmoothsynthesis
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Acknowledgements
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1.1.Experiment1–2
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2.2.Resultsanddiscussion
3.Experiment1b
3.1.Method
3.1.1.Participants
3.1.2.Materialsandprocedure
3.2.Resultsanddiscussion
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4.1.Method
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NumericalSimulationofUnsteadyFlowAroundForwardFlightHelicopterwithCoaxialRotors
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Three-dimensionalunsteadyEulerequationsarenumericallysolvedtosimulatetheunsteadyflowsaroundforwardflighthelicopterwithcoaxialrotorsbasedonunstructureddynamicoversetgrids.Theperformancesofthetwocoaxialrotorsbothbecomeworsebecauseoftheaerodynamicinteractionbetweenthem,andtheinfluenceofthetoprotoronthebottomrotorisgreaterthanthatofthebottomrotoronthetoprotor.Thedownwashvelocityatthebottomrotorplaneismuchlargerthanthatatthetoprotorplane,andthedownwashvelocityatthetoprotorplaneisalittlelargerthanthatatanindividualrotorplane.Thedownwashvelocityandthrustcoefficientbothbecomelargerwhenthecollectiveangleofbladesisadded.Whenthespacingbetweenthetwocoaxialrotorsincreases,thethrustcoefficientofthetoprotorincreases,butthetotalthrustcoefficientreducesalittle,becausethedecreaseofthebottomrotorthrustcoefficientislargerthantheincreaseofthetoprotorthrustcoefficient.
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