Aeroelastic inverse: Estimation of aerodynamic loads during large amplitude limit cycle oscillations

2020 ◽  
Vol 98 ◽  
pp. 103131
Author(s):  
Benjamin Kirschmeier ◽  
Graham Pash ◽  
Zachary Gianikos ◽  
Albert Medina ◽  
Ashok Gopalarathnam ◽  
...  
Keyword(s):  
Limit Cycle ◽  
Large Amplitude ◽  
Limit Cycle Oscillations ◽  
Aerodynamic Loads ◽  
Inverse Estimation

scholarly journals Flutter Control of a Two-Degrees-of-Freedom Airfoil Using a Nonlinear Tuned Vibration Absorber

2017 ◽  
Vol 12 (5) ◽  
Author(s):  
Arnaud Malher ◽  
Cyril Touzé ◽  
Olivier Doaré ◽  
Giuseppe Habib ◽  
Gaëtan Kerschen
Keyword(s):  
Limit Cycle ◽  
Large Amplitude ◽  
Degrees Of Freedom ◽  
Vibration Absorber ◽  
Aerodynamic Loads ◽  
Linear Approach ◽  
Aeroelastic Model ◽  
Large Amplitude Motions ◽  
Restoring Forces ◽  
Tuned Vibration Absorber

The influence of a nonlinear tuned vibration absorber (NLTVA) on the airfoil flutter is investigated. In particular, its effect on the instability threshold and the potential subcriticality of the bifurcation is analyzed. For that purpose, the airfoil is modeled using the classical pitch and plunge aeroelastic model together with a linear approach for the aerodynamic loads. Large amplitude motions of the airfoil are taken into account with nonlinear restoring forces for the pitch and plunge degrees-of-freedom. The two cases of a hardening and a softening spring behavior are investigated. The influence of each NLTVA parameter is studied, and an optimum tuning of these parameters is found. The study reveals the ability of the NLTVA to shift the instability, avoid its possible subcriticality, and reduce the limit cycle oscillations (LCOs) amplitude.

Nonlinear Aerodynamic Effects on Transonic Flap Buzz, Tail Flutter and Limit-Cycle Oscillations of Two-Dimensional Wing-Flap-Tail Configurations

2009 ◽  
Vol 25 (4) ◽  
pp. 451-463
Author(s):  
J.-C. Cheng
Keyword(s):  
Flow Regime ◽  
Limit Cycle ◽  
Transonic Flow ◽  
Large Amplitude ◽  
Two Dimensional ◽  
Limit Cycle Oscillations ◽  
Restoring Force ◽  
Tail Structure ◽  
Euler Solver ◽  
Nonlinear Aerodynamic

ABSTRACTThe transonic tail flutter and flap buzz under the wing-flap-tail configurations are analyzed utilizing a dynamic grid capability of unstructured Euler solver coupled with an appropriate aeroelastic solver. From the results, the presence of a forewing, either stationary or oscillating, has significant effect on the tail flutter characteristics. In particular, the tail motion may be in resonance with the oscillating wing before the onset of flutter, which is dangerous to the tail structure because of the large amplitude oscillations. Besides, a complicated aerodynamic and aeroelastic interference of the tail have been found due to the unsteady disturbance which is a strong variability of flow structure induced by the buzz of the flap. In the high transonic flow regime, the flap buzz with limit-cycle oscillations does occur, and the influence induced by the tail is not important. The increasing restoring force at the pivot where the flap joints with the wing will reduce the flap oscillations that improves the effect of the flap buzz.

Simulation of aircraft-pilot coupling as limit-cycle oscillations

1998 ◽  
Author(s):  
Guofeng Lin ◽  
Edward Lan ◽  
Jay Brandon
Keyword(s):  
Limit Cycle ◽  
Limit Cycle Oscillations

Sensitivity analysis of limit cycle oscillations

2012 ◽  
Vol 231 (8) ◽  
pp. 3228-3245 ◽  
Author(s):  
Joshua A. Krakos ◽  
Qiqi Wang ◽  
Steven R. Hall ◽  
David L. Darmofal
Keyword(s):  
Sensitivity Analysis ◽  
Limit Cycle ◽  
Limit Cycle Oscillations
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