|M.Sc Student||Nahom Jidovetski Tzlil|
|Subject||Wind-Tunnel Study of the ARMA Flutter Prediction Method|
|Department||Department of Aerospace Engineering||Supervisor||Professor Daniella Raveh|
Aeroelastic ﬂutter is a destructive instability phenomenon for which dedicated ﬂight test campaigns are considered compulsory according to airworthiness regulations. In these tests, the dynamic characteristics of the aeroelastic system are interpreted from measurements of the aircraft’s structural responses to external excitations. Over the years, several ﬂutter identiﬁcation and prediction techniques have been suggested in order to increase the eﬃciency of ﬂutter ﬂight tests and to enable better prediction of the ﬂutter boundary. While most of the methods rely on external mechanical excitation accessories, the Autoregressive Moving-Average (ARMA) ﬂutter prediction method attempts to identify the aeroelastic system based on the aircraft structural response to random air turbulence excitation. The study presents an experimental study of ﬂutter prediction via ARMA system identiﬁcation and the use of a linear stability parameter. The study investigates the application aspects of the methodology in a dedicated wind tunnel experiment. An elastic wing was designed and manufactured using rapid prototyping and tested in a subsonic wind tunnel all the way to ﬂutter. Structural responses were recorded by accelerometers, strain gauges, and by ﬁber-optic sensors (measuring strains). The data was processed using signal processing techniques, such as ﬁltering and averaging, and used for system identiﬁcation and ﬂutter prediction. The study focuses on the prediction characteristics and accuracy, method applicability with various dynamic data, and signal processing techniques. The study addresses practical aspects of the application of the method in a wind-tunnel test and supports the feasibility of using the ARMA method for ﬂutter ﬂight test.