TY - GEN
T1 - Analysis of complex rotor-airframe coupled instabilities by energy flow considerations
AU - Oberinger, Oliver
AU - Hajek, Manfred
PY - 2013
Y1 - 2013
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84883433594&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:84883433594
SN - 9781627486514
T3 - Annual Forum Proceedings - AHS International
SP - 390
EP - 404
BT - 69th American Helicopter Society International Annual Forum 2013
T2 - 69th American Helicopter Society International Annual Forum 2013
Y2 - 21 May 2013 through 23 May 2013
ER -