Analysis of complex rotor-airframe coupled instabilities by energy flow considerations

Oliver Oberinger, Manfred Hajek

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

This paper describes a new post-processing method for stability results obtained by comprehensive rotorcraft tools. The method provides closer physical insight into the instability mechanism of complex rotor-airframe coupling phenomena by energy flow balancing of the appropriately defined mechanical system "helicopter". The source of the instability, i.e. nature and location of energy entry into the system, can thus be identified specifically and tailored prevention means be proposed. To obtain the energy flows at the required locations, loads and motions are reconstructed mainly based on the solution of the linearized equations of motion. However, there are exceptions, where a non-linear simulation has to be performed in order to obtain physically valid results. Two example applications of the method are given in the paper: a simplified ground resonance case in vacuum and a more complex rotor-airframe coupling instability. In the first case, the known instability source is confirmed by the method and in the second case, the previously unknown instability mechanism is traced to its origin.

Original languageEnglish
Title of host publication69th American Helicopter Society International Annual Forum 2013
Pages390-404
Number of pages15
StatePublished - 2013
Event69th American Helicopter Society International Annual Forum 2013 -
Duration: 21 May 201323 May 2013

Publication series

NameAnnual Forum Proceedings - AHS International
Volume1
ISSN (Print)1552-2938

Conference

Conference69th American Helicopter Society International Annual Forum 2013
Period21/05/1323/05/13

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